NeuroMetrix, Inc.

Schedule II — Valuation and Qualifying Accounts

Description of Business and Basis of Presentation

1. Description of Business and Basis of Presentation

NeuroMetrix, Inc., or the Company, a Delaware corporation, was founded in June 1996. The Company develops wearable medical technology and point-of-care tests that help patients and physicians better manage chronic pain, nerve diseases, and sleep disorders. The Company markets Quell^® and SENSUS® which are wearable therapeutic devices designed for relief of chronic, intractable pain. Quell was commercially launched in the United States during the second quarter of 2015. The Company also markets DPNCheck®, which is a quantitative nerve conduction test that is used by physicians and health care professionals to evaluate systemic neuropathies such as diabetic peripheral neuropathy, or DPN. The Company’s historical neurodiagnostic business is based on the ADVANCE^TM System which is a comprehensive platform for the performance of traditional nerve conduction studies and invasive electromyography procedures and which is primarily used in physician offices and clinics.

During 2015 the Company completed two equity offering which are detailed in Note 12 to the financial statements. These financings resulted in proceeds of approximately $19.0 million after redemptions of certain equity instruments, and before fees and expenses. After deducting financial institution discounts and fees, and other expenses of the offerings, the Company realized net proceeds of approximately $16.8 million

The accompanying financial statements have been prepared on a basis which assumes that the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The Company has suffered recurring losses from operations and negative cash flows from operating activities. At December 31, 2015, the Company had an accumulated deficit of $163.6 million. The Company held cash and cash equivalents of $12.5 million as of December 31, 2015. The Company believes that these resources and the cash to be generated from expected product sales will be sufficient to meet its projected operating requirements through the second quarter of 2016. The Company continues to face significant challenges and uncertainties and, as a result, the Company’s available capital resources may be consumed more rapidly than currently expected due to (a) decreases in sales of the Company’s products and the uncertainty of future revenues from new products; (b) changes the Company may make to the business that affect ongoing operating expenses; (c) changes the Company may make in its business strategy; (d) regulatory developments affecting the Company’s existing products; (e) changes the Company may make in its research and development spending plans; and (f) other items affecting the Company’s forecasted level of expenditures and use of cash resources. Accordingly, the Company will need to raise additional funds to support its operating and capital needs in the third quarter of 2016 and beyond. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. The Company intends to obtain additional funding through public or private financing, collaborative arrangements with strategic partners, or through additional credit lines or other debt financing sources to increase the funds available to fund operations. However, the Company may not be able to secure such financing in a timely manner or on favorable terms, if at all. Furthermore, if the Company issues equity or debt securities to raise additional funds, its existing stockholders may experience dilution, and the new equity or debt securities may have rights, preferences and privileges senior to those of the Company’s existing stockholders. If the Company raises additional funds through collaboration, licensing or other similar arrangements, it may be necessary to relinquish valuable rights to its potential products or proprietary technologies, or grant licenses on terms that are not favorable to the Company. Without additional funds, the Company may be forced to delay, scale back or eliminate some of its sales and marketing efforts, research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations. If any of these events occurs, the Company’s ability to achieve its development and commercialization goals would be adversely affected.

Certain prior period amounts have been adjusted to reflect the Company's 1-for-4 reverse stock split effected December 2015 (see Note 13, Reverse Stock Split, for further details).

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of Estimates and Assumptions

The preparation of financial statements in conformity with United States generally accepted accounting principles requires management to make significant estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during reporting periods. Actual results could differ from those estimates.

The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances and regularly assesses these estimates, but actual results could differ materially from these estimates. Effects of changes in estimates are recorded in the period in which they occur.

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of ninety days or less to be cash equivalents. Cash equivalents are recorded at cost which approximates fair value. The Company invests cash primarily in a money market account and other investments which management believes are subject to minimal credit and market risk.

Concentrations of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents in bank deposit accounts and trade receivables. The Company invests its funds in highly rated institutions and limits its investment in any individual account so that they do not exceed FDIC limits. The Company has not experienced significant losses related to cash and cash equivalents and does not believe it is exposed to any significant credit risks relating to its cash and cash equivalents.

At December 31, 2015, one customer accounted for 46% of accounts receivable. For the year ended December 31, 2015 one customer accounted for 12% of revenue. For the year ended December 31, 2014 one customer accounted for more than 30% of revenue. For the year ended December 31, 2013, one customer accounted for more than 10% of revenue.

The Company relies on in-house assembly and three third-party manufacturers to manufacture the major portion of its current products and product components. The disruption or termination of the supply of these products or a significant increase in the cost of these products from these sources could have an adverse effect on the Company’s business, financial position, and results of operations.

Inventories

Inventories, consisting primarily of finished goods and purchased components, are stated at the lower of cost or market. Cost is determined using the first-in, first-out method. The Company writes down inventory to its net realizable value for excess or obsolete inventory. Finished goods inventories owned by the Company, but stored in third party warehouses prior to order fulfillment, are disclosed separately as finished goods on consignment.

Fair Value

The carrying amounts of the Company’s accounts receivable, accounts payable, and accrued expenses approximate their fair value at December 31, 2015 and 2014 due to the short-term nature of these assets and liabilities. The Company’s cash equivalents and its warrant liability are carried at fair value determined according to the fair value hierarchy described in Note 9.

Revenue Recognition

The Company recognizes revenue when the following criteria have been met: persuasive evidence of an arrangement exists, delivery has occurred and risk of loss has passed, the seller’s price to the buyer is fixed or determinable, and collection is reasonably assured.

Revenues associated with the Company’s medical devices and consumables, including single use nerve specific electrodes and other accessories are generally recognized upon shipment, assuming all other revenue criteria have been met.

Revenue recognition involves judgments, including assessments of expected returns and expected customer relationship periods. The Company analyzes various factors, including a review of specific transactions, its historical product returns, average customer relationship periods, customer usage, customer balances, and market and economic conditions. Changes in judgments or estimates on these factors could materially impact the timing and amount of revenues and costs recognized. Should market or economic conditions deteriorate, the Company’s actual return or bad debt experience could exceed its estimate. Certain product sales are made with a 30-day or 60-day right of return. Where the Company can reasonably estimate future returns, it recognizes revenues upon shipment and records as a reduction of revenue a provision for estimated returns. Where the Company cannot reasonably estimate future returns, it defers revenues until it gains sufficient experience to estimate returns or until the right of return lapses.

Accounts Receivable

Accounts receivable are recorded net of the allowance for doubtful accounts receivable. The allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses in our existing accounts receivable. The Company reviews the allowance for doubtful accounts and determines the allowance based on an analysis of customer past payment history, product usage activity, and recent communications with the customer. Individual customer balances which are past due and over 90 days outstanding are reviewed individually for collectability. Account balances are written-off against the allowance when the Company feels it is probable the receivable will not be recovered. The Company does not have any off-balance sheet credit exposure related to our customers.

Income Taxes

The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company’s financial statements contain certain deferred tax assets, which have arisen primarily as a result of operating losses, as well as other temporary differences between financial and tax accounting. In accordance with the provisions of the Income Taxes topic of the Codification, the Company is required to establish a valuation allowance if the likelihood of realization of the deferred tax assets is reduced based on an evaluation of objective verifiable evidence. Significant management judgment is required in determining the Company’s provision for income taxes, the Company’s deferred tax assets and liabilities and any valuation allowance recorded against those net deferred tax assets. The Company evaluates the weight of all available evidence to determine whether it is more likely than not that some portion or all of the net deferred income tax assets will not be realized.

Utilization of the NOL and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred previously or that could occur in the future, as provided by Section 382 of the Internal Revenue Code of 1986, as well as similar state provisions. Ownership changes may limit the amount of NOL and tax credit carryforwards that can be utilized to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain shareholders or public groups in the stock of a corporation by more than 50 percentage points over a three-year period. If the Company has experienced a change of control, utilization of its NOL or tax credits carryforwards would be subject to an annual limitation under Section 382. Any limitation may result in expiration of a portion of the NOL or research and development credit carryforwards before utilization. Subsequent ownership changes could further impact the limitation in future years. Further, until a study is completed and any limitation known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s NOL carryforwards and research and development credit carryforwards and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the balance sheet or statement of operations if an adjustment were required.

Management performed a two-step evaluation of all tax positions, ensuring that these tax return positions meet the “more likely than not” recognition threshold and can be measured with sufficient precision to determine the benefit recognized in the financial statements. These evaluations provide management with a comprehensive model for how a company should recognize, measure, present, and disclose in its financial statements certain tax positions that the Company has taken or expects to take on income tax returns.

Research and Development

Costs incurred in research and development are expensed as incurred. Included in research and development costs are wages, benefits, product design consulting, and other operating costs such as facilities, supplies, and overhead directly related to the Company’s research and development efforts.

Product Warranty Costs

The Company accrues estimated product warranty costs at the time of sale which are included in cost of sales in the statements of operations. The amount of the accrued warranty liability is based on historical information such as past experience, product failure rates, number of units repaired, and estimated cost of material and labor. The liabilities for product warranty costs of $10,484 and $1,784 at December 31, 2015 and 2014, respectively, are included in accrued expenses in the accompanying balance sheets.

Fixed Assets and Long-Lived Assets

Fixed assets are recorded at cost and depreciated using the straight-line method over the estimated useful life of each asset. Expenditures for repairs and maintenance are charged to expense as incurred. On disposal, the related assets and accumulated depreciation are eliminated from the accounts and any resulting gain or loss is included in the Company’s statement of operations. Leasehold improvements are amortized over the shorter of the estimated useful life of the improvement or the remaining term of the lease.

The Company periodically evaluates the recoverability of its fixed assets and other long-lived assets whenever events or changes in circumstances indicate that an event of impairment may have occurred. This periodic review may result in an adjustment of estimated depreciable lives or asset impairment. When indicators of impairment are present, the carrying values of the asset are evaluated in relation to the assets operating performance and future undiscounted cash flows of the underlying assets. If the future undiscounted cash flows are less than their book value, an impairment may exist. The impairment is measured as the difference between the book value and the fair value of the underlying asset. Fair values are based on estimates of the market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk.

Accounting for Stock-Based Compensation

Stock-based compensation cost is generally recognized ratably over the requisite service period. The Company uses the Black-Scholes option pricing model for determining the fair value of its stock options and amortizes its stock-based compensation expense using the straight-line method. The Black-Scholes model requires certain assumptions that involve judgment. Such assumptions are the expected share price volatility, expected life of options, expected annual dividend yield, and risk-free interest rate (See Note 3 — Stock-Based Compensation and Stockholders’ Equity).

Net Loss per Common Share

Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of common shares outstanding during the period. Unvested restricted shares, although legally issued and outstanding, are not considered outstanding for purposes of calculating basic net loss per common share. Diluted net loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding during the period plus the dilutive effect of the weighted average number of outstanding instruments such as options, warrants, restricted stock, and preferred stock. Because the Company has reported a net loss for all periods presented, diluted loss per common share is the same as basic loss per common share, as the effect of utilizing the fully diluted share count would have reduced the net loss per common share. Therefore, in calculating net loss per share amounts, shares underlying the following potentially dilutive weighted average number of common stock equivalents were excluded from the calculation of diluted net loss per common share because their effect was anti-dilutive for each of the periods presented:


	Years Ended December 31,
	2015		2014		2013
Options		208,135		125,207		40,348
Warrants		3,222,071		609,084		513,933
Unvested restricted stock		80		1,122		5,597
Convertible preferred stock		2,264,086		228,143		—
Total		5,694,372		963,556		559,878

The Beneficial Conversion Feature, or BCF, recorded in the 2015, 2014 and 2013 Offerings have been recognized as deemed dividends. In addition, the difference between the fair value of the consideration received and the recorded book value of equity instruments redeemed in the December 2015 Offering has been recognized as a deemed dividend. These items have been reflected as an adjustment in the calculation of earnings per share. See Note 12, Stockholders’ Equity, for further details.

Net loss per common share applicable to common stockholders, basic and diluted was determined as follows:


	Years Ended December 31,
	2015			2014			2013
Net loss	$	(9,187,348	)	$	(7,766,222	)	$	(8,019,137	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		(4,140,446	)		(2,955,668	)		(766,872	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(8,332,212	)		—			—
Return of capital to common shareholders attributable to the repurchase of preferred shares and related embedded beneficial conversion feature		589,751			—			—
Net loss applicable to common stockholders	$	(21,070,255	)	$	(10,721,890	)	$	(8,786,009	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.75	)	$	(6.15	)	$	(12.28	)
Weighted average number of common shares outstanding, basic and diluted		2,719,285			1,743,494			715,524

Advertising and Promotional Costs

Advertising and promotional costs are expensed as incurred. Advertising and promotion expense was $2,499,000, $481,000, and $151,000, in 2015, 2014, and 2013, respectively.

Accumulated Other Comprehensive Items

For 2015, 2014, and 2013, the Company had no components of other comprehensive income or loss other than net loss.

Segments

The Company operates in one segment for the sale of medical equipment and consumables. Substantially all of the Company’s assets, revenues, and expenses for 2015, 2014, and 2013 were located at or derived from operations in the United States. Revenues from sales outside the United States accounted for approximately 19% of total revenues in 2015, 19% of total revenues in 2014, and 16% of total revenues in 2013.

Risks and Uncertainties

The Company is subject to risks common to companies in the medical device industry, including, but not limited to, development by the Company or its competitors of new technological innovations, dependence on key personnel, customers’ reimbursement from third-party payers, protection of proprietary technology, and compliance with regulations of the FDA and other governmental agencies.

Recently Issued or Adopted Accounting Pronouncements

In November 2015, the FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes (ASU 2015-17). ASU 2015-17 requires that deferred income tax liabilities and assets be classified as noncurrent in the Company’s balance sheet. The standard is effective for public entities for annual and interim periods beginning after December 15, 2016, with early adoption permitted. ASU 2015-17 has been adopted on a prospective basis by the Company for the year ended December 31, 2015, thus resulting in the reclassification of $45,000 of current deferred tax liabilities to noncurrent on the accompanying consolidated balance sheet. The prior reporting period was not retrospectively adjusted. The adoption of this guidance had no impact on the Company’s results of operations or cash flows.

In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15). ASU 2014-15 requires management to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The standard is effective for public entities for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company is evaluating the provisions of ASU 2014-15 and assessing the impact, if any, it may have on financial position, results of operations or cash flows.

In May 2014, the FASB and the International Accounting Standards Board (“IASB”) jointly issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), a comprehensive new revenue recognition standard that will supersede nearly all existing revenue recognition guidance. The objective of ASU 2014-09 is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 will be effective for the first quarter of 2017. An entity can elect to adopt ASU 2014-09 using one of two methods, either full retrospective adoption to each prior reporting period, or recognizing the cumulative effect of adoption at the date of initial application. The Company is in the process of evaluating the new standard and does not know the effect, if any, ASU 2014-09 will have on the Consolidated Financial

Stock-Based Compensation

12 Months Ended

Dec. 31, 2015

Share-based Compensation [Abstract]

Stock-Based Compensation

3. Stock-Based Compensation

During 2004, the Company adopted the 2004 Stock Option and Incentive Plan, as amended and restated most recently in 2015. At the Annual Meeting of Stockholders held on May 5, 2015, the stockholders of the Company approved the Company’s Seventh Amended and Restated 2004 Stock Option and Incentive Plan (the “2004 Stock Plan”), which, among other things, increased the number of shares of the Company’s common stock authorized for issuance thereunder by 212,500 shares. The 2004 Stock Plan, among other things, provides for granting of incentive and nonqualified stock option and stock bonus awards to officers, employees and outside consultants. Outstanding options under the 2004 Stock Plan generally vest over three or four years and terminate 10 years after the grant date, or earlier if the option holder is no longer an executive officer, employee, consultant, advisor or director, as applicable, of the Company. As of December 31, 2015, 531,570 shares of common stock were authorized for issuance under the 2004 Stock Plan, of which 94,703 shares had been issued, 164,813 shares were subject to outstanding options at a weighted average exercise price of $22.23 per share and 272,054 shares were available for future grant.

During May 2009, the Company adopted the 2009 Non-Qualified Inducement Stock Plan (the “2009 Inducement Plan”). The 2009 Inducement Plan is intended to encourage and enable employees, including prospective employees, of the Company upon whose judgment, initiative, and efforts the Company largely depends for the successful conduct of its business to acquire a proprietary interest in the Company. The 2009 Inducement Plan, among other things, provides for the granting of awards, including non-qualified stock options, restricted stock, and unrestricted stock. As of December 31, 2015, 100,000 shares of common stock were authorized for issuance under the 2009 Inducement Plan, of which 50,000 shares had been issued and were outstanding.

The exercise price of stock options awarded under the 2004 Stock Plan and the 2009 Inducement Plan may not be less than the fair market value of the common stock on the date of the option grant. For holders of more than 10% of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110% of the fair market value of the Company’s common stock at the date of grant and for a term not to exceed five years.

In June 2004, the Company adopted the 2004 Employee Stock Purchase Plan (the “2004 ESPP”). All of the Company’s employees who had been employed by the Company for at least 60 days and whose customary employment is for more than 20 hours per week and for more than five months in any calendar year were eligible to participate and any employee who owned 5% or more of the voting power or value of the Company’s stock was not eligible to participate. The 2004 ESPP authorized the issuance of up to a total of 2,604 shares of the Company’s common stock to participating employees.

In May 2010, the Company adopted the 2010 Employee Stock Purchase Plan (the “2010 ESPP”). The 2010 ESPP initially authorized the issuance of up to a total of 1,736 shares, of the Company’s common stock to participating employees plus an annual increase on the first day of each of the Company's fiscal years beginning in 2011, equal to the lesser of (i) 1,736 shares, (ii) 1 percent of the shares of common stock outstanding on the last day of the immediately preceding fiscal year, or (iii) such lesser number of shares as is determined by the Board. At the Company’s Annual Meeting of Stockholders held on May 14, 2012, the stockholders of the Company approved the Company’s Amended and Restated 2010 Employee Stock Purchase Plan (the “Amended and Restated 2010 ESPP”), which, among other things, increased the number of shares of the Company’s common stock authorized for issuance thereunder by 4,167 shares. All of the Company’s full-time employees and certain part-time employees are eligible to participate in the Amended and Restated 2010 ESPP. For part-time employees to be eligible, they must have customary employment of more than five months in any calendar year and more than 20 hours per week. Employees who, after exercising their rights to purchase shares under the Amended and Restated 2010 ESPP, would own shares representing 5% or more of the voting power of the Company’s common stock, are ineligible to participate.

Under the Amended and Restated 2010 ESPP, participating employees can authorize the Company to withhold up to 10% of their earnings during consecutive six-month payment periods for the purchase of the shares. At the conclusion of each period, participating employees can purchase shares at 85% of the lower of their fair market value at the beginning or end of the period. The Amended and Restated 2010 ESPP is regarded as a compensatory plan. For the years ended December 31, 2015 and 2014 the Company issued 15,443 and 3,681 shares of its common stock, respectively, under the Amended and Restated 2010 ESPP and the 2010 ESPP, respectively. As of December 31, 2015, there were 19,792 remaining shares to be issued under the Amended and Restated 2010 ESPP.

The Company uses the Black-Scholes option pricing model for determining the fair value of shares of common stock issued or to be issued under the 2010 ESPP and the Amended and Restated 2010 ESPP. The following assumptions are used in determining fair value: The risk-free interest rate assumption is based on the United States Treasury’s constant maturity rate for a six month term (corresponding to the expected option term) on the date the option was granted. The expected dividend yield is zero because the Company does not currently pay dividends nor expects to do so during the expected option term. An expected term of six months is used based on the duration of each plan offering period. The volatility assumption is based on a consideration of stock price volatility over the most recent period of time corresponding to the expected term and is also based on expected future stock price volatility.

The weighted average grant-date fair value of stock options used in the calculation of stock-based compensation expense in the accompanying statement of operations for the years ended December 31, 2015, 2014, and 2013 is calculated using the following assumptions:


	Years Ended December 31,
	2015			2014			2013
Risk-free interest rate		1.3 – 1.7%			1.4 – 1.8%			1.4 – 1.7%
Expected dividend yield		—			—			—
Expected option term		5 years			5 years			5 years
Volatility		70.0	%		70.0	%		70.0	%

The risk-free interest rate assumption is based on the United States Treasury’s constant maturity rate for a five year term (corresponding to the expected option term) on the date the option was granted. The expected dividend yield is zero as the Company does not currently pay dividends nor expects to do so during the expected option term. The expected option term of five years is estimated based on an analysis of actual option exercises. The volatility assumption is based on daily historical volatility during the time period that corresponds to the expected option term and expected future stock price volatility. The pre-vesting forfeiture rate is based on the historical and projected average turnover rate of employees.

A summary of option activity for the year ended December 31, 2015 is presented below:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2014		190,481		$	20.67
Granted		31,376			5.07
Exercised		—			—
Forfeited		(7,044	)		8.05
Expired		—			—
Outstanding at December 31, 2015		214,813			18.81		8.3	$	0
Vested or expected to vest at December 31, 2015		204,310			19.45		7.9		0
Exercisable at December 31, 2015		118,822			28.67		8.3		0

Expected to vest options are determined by applying the pre-vesting forfeiture rate to the total outstanding options. Aggregate intrinsic value represents the total pre-tax intrinsic value (the aggregate difference between the closing stock price of the Company’s common stock as of December 31, 2015, as applicable, and the exercise price for the in-the-money options) that would have been received by the option holders if all the in-the-money options had been exercised on December 31, 2015.

The weighted average per share grant-date fair values of options granted during 2015, 2014, and 2013 was $2.95, $4.24, and $4.08, respectively.

The aggregate intrinsic value of options issued or exercised during 2015, 2014, and 2013 was $0.

Total unrecognized stock-based compensation costs related to non-vested stock options was $288,000, which related to 214,813 shares with a per share weighted fair value of $11.18 as of December 31, 2015. This unrecognized cost is expected to be recognized over a weighted average period of approximately 2.1 years.

Stock options granted to non-employees are recorded at fair value and adjusted to market over the vesting period. The Company determines fair value using the Black-Scholes option pricing model, an expected term equal to the option term, a risk-free interest rate corresponding to the expected term, a stock price volatility over the most recent period of time corresponding to the expected term and also based on expected future stock price volatility, and a dividend yield of zero. There were no options granted to non-employees during the years ended December 31, 2015, 2014 or 2013.

Beginning in 2010, certain employees have been granted restricted stock. There were no restricted stock grants in 2015 and 2014. During 2013, the Company granted 500 shares of restricted stock. The restricted stock vested based on continued employment. The fair value of restricted stock is calculated based on the closing sale price of the Company’s common stock on the date of issuance.

A summary of restricted stock activity for the year ended December 31, 2015 is presented below:


	Restricted Shares			Weighted Average Grant Date Fair Value
Restricted shares at December 31, 2014		208		$	7.60
Granted		—			—
Vested		(208	)		(7.60	)
Canceled		—			—
Restricted shares at December 31, 2015		—		$	—

During 2015, 2014, and 2013, in lieu of paying withholding taxes on the vesting of restricted stock, an aggregate of 0, 0, and 1,054 shares, respectively, of common stock were withheld to satisfy the minimum tax withholding requirements related to such vesting. Shares withheld were calculated using the market price of the common stock.

Cash received from option exercises and purchases under the 2004 ESPP and the 2010 ESPP for the years 2015, 2014, and 2013, was $38,000, $24,000, and $26,000, respectively. The Company issues new shares upon option exercises, purchases under the Company’s ESPPs, and vesting of restricted stock.

The Company recorded stock-based compensation expense of $302,000, $290,000, and $246,000 for 2015, 2014, and 2013, respectively.

Inventories

12 Months Ended

Dec. 31, 2015

Inventory Disclosure [Abstract]

Inventories

4. Inventories

Inventories consist of the following:

	December 31,
	2015		2014
Purchased components	$	432,437	$	209,426
Finished goods on consignment		39,784		—
Finished goods		616,863		470,314
	$	1,089,084	$	679,740

Fixed Assets

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Fixed Assets

5. Fixed Assets

Fixed assets consist of the following:


	Estimated Useful Life (Years)			December 31,
	Estimated Useful Life (Years)			2015			2014
Construction in process				$	—		$	182,755
Computer and laboratory equipment		3			1,698,390			1,782,330
Furniture and equipment		3			319,046			109,617
Production equipment		7			864,287			745,596
Leasehold improvements			*		117,994			7,268
					2,999,717			2,827,566
Less – accumulated depreciation					(2,316,183	)		(2,516,046	)
				$	683,534		$	311,520

Lesser of life of lease or estimated useful life.

Depreciation expense was $222,592, $145,100, and $150,663 for 2015, 2014, and 2013, respectively.

Accrued Compensation and Expenses

12 Months Ended

Dec. 31, 2015

Payables and Accruals [Abstract]

Accrued Compensation and Expenses

6. Accrued Compensation and Expenses

The following table provides a rollforward of the liability balance for severance obligations which was recorded as research and development expense in the Company’s Statement of Operations for the year ended 2014. The balance as of December 31, 2014 was included as a component of accrued compensation on the balance sheet.


	December 31,
	2015			2014
Balance – beginning	$	148,921		$	110,608
Accrual for severance		—			302,758
Severance payments made		(148,921	)		(264,445	)
Balance – ending	$	—		$	148,921

Accrued expenses consist of the following for the years ended December 31, 2015 and 2014:

	December 31,
	2015		2014
Technology fees	$	450,000	$	450,000
Professional services		336,229		257,024
Consulting fees		92,000		173,759
Clinical study obligations		—		74,000
Sales taxes		56,284		34,206
Personnel related obligations		15,548		37,761
Federal excise tax		1,023		25,989
Other		104,399		212,137
	$	1,055,483	$	1,264,876

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Income Taxes

7. Income Taxes

Current income tax expense (benefit) attributable to continuing operations was zero for the years ended December 31, 2015, 2014, and 2013.

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2015, 2014, and 2013.


	Years Ended December 31,
	2015			2014			2013
Federal tax provision (benefit) rate		(34.0	)%		(34.0	)%		(34.0	)%
State tax provision, net of federal provision		(8.5	)		(7.0	)		(4.8	)
Permanent items		(14.5	)		(3.6	)		3.4
Federal research and development credits		(1.3	)		(1.0	)		(1.7	)
Expiration of tax attribute		—			10.9			—
Valuation allowance		58.3			34.7			37.1
Effective income tax rate		—	%		—	%		—	%

The Company’s deferred tax assets consist of the following:


	December 31,
	2015			2014
Deferred tax assets:
Net operating loss carryforwards	$	40,397,318		$	35,449,695
Research and development credit carryforwards		2,005,741			1,855,586
Accrued expenses		704,957			657,132
Stock-based compensation		538,321			590,006
Other		13,698			13,506
Total gross deferred tax assets		43,660,035			38,565,925
Valuation allowance		(43,660,035	)		(38,565,925	)
Net deferred tax assets	$	—		$	—

At December 31, 2015, the Company has federal and state net operating loss carryforwards (“NOL”) of $118.2 million and $34.9 million, respectively, as well as federal and state tax credits of $1.3 million and $1.1 million, respectively, which may be available to reduce future taxable income and the related taxes thereon. This amount includes tax benefits of $3.9 million and $71,000 attributable to NOL and tax credit carryforwards, respectively, that result from the exercise of employee stock options. The tax benefit of these items will be recorded as a credit to additional paid-in capital upon realization of the deferred tax asset or reduction in income taxes payable. The federal NOL’s begin to expire in 2019 and the state NOL’s begin to expire in 2017. The federal and state research and development credits both begin to expire in 2018.

In accordance with the provisions of the Income Taxes topic of the Codification, the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating losses. Management has determined that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets and, as a result, a valuation allowance of approximately and $43.8 million and $38.6 million has been established at December 31, 2015 and 2014, respectively. Utilization of the NOL and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred previously or that could occur in the future, as provided by Section 382 of the Internal Revenue Code of 1986, as well as similar state provisions. Ownership changes may limit the amount of NOL and tax credit carryforwards that can be utilized to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain shareholders or public groups in the stock of a corporation by more than 50 percentage points over a three-year period. If the Company has experienced a change of control, utilization of its NOL or tax credits carryforwards would be subject to an annual limitation under Section 382. Any limitation may result in expiration of a portion of the NOL or research and development credit carryforwards before utilization. Subsequent ownership changes could further impact the limitation in future years. Further, until a study is completed and any limitation known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s NOL carryforwards and research and development credit carryforwards and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the balance sheet or statement of operations if an adjustment were required.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

8. Commitments and Contingencies

Operating Leases

In August 2014, the Company entered into a 5-year operating lease agreement with one 5-year extension option for manufacturing and order fulfillment facilities in Woburn, Massachusetts (the “Woburn Lease”). The Woburn Lease commenced December 15, 2014 and has a monthly base rent of $7,503. In September 2014, the Company entered into a 7-year operating lease agreement with one 5-year extension option for its corporate office and product development activities in Waltham, Massachusetts (the “Waltham Lease”). The term of the Waltham Lease commenced on February 20, 2015 and includes fixed payment obligations that escalate over the initial lease term. Average monthly base rent under the 7-year lease is approximately $37,792. These payment obligations will be accrued and recognized over the term of occupancy such that rent expense is recognized on a straight-line basis. Under the Waltham Lease, the landlord was responsible for making certain improvements to the leased space at an agreed upon cost to the landlord. The landlord and the Company mutually agreed to make improvements in excess of the agreed upon landlord cost, and the landlord billed that excess cost to the Company as additional rent. This additional rent of $275,961 was included in the net calculation of lease payments, so that rent expense is recognized on a straight-line basis over the remaining term of occupancy.

Future minimum lease payments under non-cancellable operating leases as of December 31, 2015 are as follows:


2016		517,566
2017		529,537
2018		541,508
2019		553,479
2020		475,408
2021		487,379
2022		81,562
Total minimum lease payments	$	3,186,439

Total recorded rent expense was $679,026, $638,679, and $635,004, for the 2015, 2014, and 2013, respectively. The Company records rent expense on its facility lease on a straight-line basis over the lease term.

Other Commitments

At December 31, 2015, other commitments, comprised of purchase orders, totaled approximately $1,526,459.

Fair Value Measurements

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

9. Fair Value Measurements

The Fair Value Measurements and Disclosures Topic of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (the “Codification”) defines fair value, establishes a framework for measuring fair value in applying generally accepted accounting principles, and expands disclosures about fair value measurements. This Codification topic identifies two kinds of inputs that are used to determine the fair value of assets and liabilities: observable and unobservable. Observable inputs are based on market data or independent sources while unobservable inputs are based on the Company’s own market assumptions. Once inputs have been characterized, this Codification topic requires companies to prioritize the inputs used to measure fair value into one of three broad levels. Fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values identified by Level 2 inputs utilize observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. Fair values identified by Level 3 inputs are unobservable data points and are used to measure fair value to the extent that observable inputs are not available. Unobservable inputs reflect the Company’s own assumptions about the assumptions that market participants would use at pricing the asset or liability.

The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis for the periods presented and indicates the fair value hierarchy of the valuation techniques it utilized to determine such fair value. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are observable such as quoted prices, interest rates, and yield curves. Fair values determined by Level 3 inputs are unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability.


	December 31, 2015		Fair Value Measurements at December 31, 2015 Using
	December 31, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	1,865,498	$	1,865,498	$	—	$	—
Total	$	1,865,498	$	1,865,498	$	—	$	—
Liabilities:
Common stock warrants	$	280,303	$	—	$	—	$	280,303
Total	$	280,303	$	—	$	—	$	280,303

Due to the lack of market quotes relating to our common stock warrants, the fair value of the common stock warrants was determined at December 31, 2015 using the Black-Scholes model, which is based on Level 3 inputs. As of December 31, 2015, inputs used in the Black-Scholes model are presented below. The assumptions used may change as the underlying sources of these assumptions and market conditions change. Based on the Black-Scholes model, the Company recorded a common stock warrants liability of $0.3 million at December 31, 2015.


	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2015
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	1.98	$	8.16		73.39	%		1.42	%		3yr 6mo		none
2013 Offering	$	1.98	$	8.00		70.42	%		1.17	%		2yr 5mo		none

The following table provides a summary of changes in the fair value of the Company’s Level 3 financial liabilities between December 31, 2013 and December 31, 2015.


	2014 Offering			2013 Offering			Total
Balance at December 31, 2013	$	—		$	1,938,603		$	1,938,603
Initial fair value of warrants at issuance in June 2014		4,418,824			—			4,418,824
Change in fair value of warrant liability		(185,095	)		(865,000	)		(1,050,095	)
Balance at December 31, 2014	$	4,233,729		$	1,073,603		$	5,307,332
Repurchase of warrants in conjunction with public offering		(943,423	)		—			(943,423	)
Change in fair value of warrant liability		(3,062,314	)		(1,021,292	)		(4,083,606	)
Balance at December 31, 2015	$	227,992		$	52,311		$	280,303


	December 31, 2014		Fair Value Measurements at December 31, 2014 Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	4,107,478	$	4,107,478	$	—	$	—
Total	$	4,107,478	$	4,107,478	$	—	$	—
Liabilities:
Common stock warrants	$	5,307,307	$	—	$	—	$	5,307,307
Total	$	5,307,307	$	—	$	—	$	5,307,307

Due to the lack of market quotes relating to our common stock warrants, the fair value of the common stock warrants was determined at December 31, 2014 using the Black-Scholes model, which is based on Level 3 inputs. As of December 31, 2014, inputs used in the Black-Scholes model are presented below. The assumptions used may change as the underlying sources of these assumptions and market conditions change. Based on the Black-Scholes model, the Company recorded a common stock warrants liability of $5.3 million at December 31, 2014.


	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2014
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	7.80	$	8.16		71.11	%		1.51	%		4yr 6mo		none
2013 Offering	$	7.80	$	8.00		75.71	%		1.24	%		3yr 5mo		none

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Retirement Plan

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Retirement Plan

10. Retirement Plan

The Company has established a 401(k) defined contribution savings plan for its employees who meet certain service period and age requirements. Contributions are permitted up to the maximum allowed under the Internal Revenue Code of each covered employee’s salary. The savings plan permits the Company to contribute at its discretion. In 2015, 2014 and 2013 the Company made no contributions to the plan.

Credit Facility

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Credit Facility

11. Credit Facility

The Company is party to a Loan and Security Agreement, or the Credit Facility, with a bank. As of December 31, 2015 the Credit Facility permitted the Company to borrow up to $2.5 million on a revolving basis. The Credit Facility was subsequently amended, most recently on January 14, 2016, and extended until January 15, 2017. Amounts borrowed under the Credit Facility will bear interest equal to the prime rate plus 0.5%. Any borrowings under the Credit Facility will be collateralized by the Company’s cash, accounts receivable, inventory, and equipment. As of December 31, 2015 the Company was in default under a provision of the Credit Facility that requires the prior written consent by the bank for any repurchase on the Company’s capital stock. This default was waived by the bank on January 14, 2016. The Credit Facility also includes traditional lending and reporting covenants. These include certain financial covenants applicable to liquidity that are to be maintained by the Company. As of December 31, 2015, the Company was in compliance with these covenants and had not borrowed any funds under the Credit Facility. However, $226,731 of the amount available under the Credit Facility is restricted to support letters of credit issued in favor of the Company’s landlords for the Waltham Lease. Consequently, the amount available for borrowing under the Credit Facility as of December 31, 2015 was $2.3 million.

Stockholders' Equity

12 Months Ended

Dec. 31, 2015

Stockholders' Equity Note [Abstract]

Stockholders' Equity

12. Stockholders’ Equity

Private and Public Offerings of Common Stock and Warrants

In December 2015, the Company completed a private equity offering and issued (i) 13,800 shares of Series C convertible preferred stock (the “Series C Preferred Stock”) at a price of $1,000 per share, and (ii) warrants (the “Warrants”) to purchase up to 10,823,528 shares of common stock, par value $0.0001 per share (the “Common Stock”), at an exercise price of $2.30 per share (the “December 2015 Offering”). As a part of this offering, the Company redeemed 63,000 Series B preferred shares from the May 2015 Offering that were held by the investor. Accordingly, the December 2015 Offering resulted in proceeds of $7.5 million. After underwriting discounts, commission and expenses, net proceeds of the offering were $6.7 million.

Each share of Series C Preferred Stock had a stated value of $1,000 and is convertible at the option of the holder into the number of shares of common stock determined by dividing the stated value by the conversion price of $2.55, which is subject to adjustment as provided in the Certificate of Designation for the Series C Preferred Stock. The Series C Preferred Stock has no dividend rights, liquidation preference or other preferences over common stock and has no voting rights except as provided in the Certificate of Designation for the Series C Preferred Stock and as required by law.

The December 2015 Offering was accounted for as a modification of the investor’s Series B Preferred Stock. Under the modification model, the difference between the fair value of the newly issued Series C Preferred Stock and the Warrants and the carrying value of the repurchased Series B Preferred Stock was recognized within retained earnings as a deemed dividend. The amount of the deemed dividend totaled $8,332,212. As of December 31, 2015, all of the newly issued Series C Preferred Stock were outstanding.

In May 2015, the Company completed an underwritten public offering (the “May 2015 Offering”) of (i) 147,000 shares of Series B Preferred Stock (the “Series B Preferred Stock”) at a price of $100 per share, and (ii) five year warrants to purchase up to 3,638,250 shares of common stock with an exercise price of $5.00 per share. The May 2015 Offering resulted in approximately $14.7 million in gross proceeds, before deducting underwriting discounts and commission and expenses. In conjunction with the 2015 Offering, approximately $3.2 million of the proceeds were used to repurchase the outstanding Series A-4 preferred shares from the 2014 Offering (described below). Net proceeds from the May 2015 Offering, after deducting underwriting discount and commissions and offering expenses and repurchase of outstanding Series A-4 preferred shares, were approximately $10.1 million.

Each share of Series B Preferred Stock had a stated value of $100 and is convertible at the option of the holder into the number of shares of common stock determined by dividing the stated value by the conversion price of $4.0404, which is subject to adjustment as provided in the Certificate of Designation for the Series B Preferred Stock. The Series B Preferred Stock has no dividend rights, liquidation preference or other preferences over common stock and has no voting rights except as provided in the Certificate of Designation for the Series B Preferred Stock and as required by law.

The Series B Preferred Stock is convertible into an aggregate of 3,638,250 shares of common stock. During the second quarter of 2015, 24,684 shares of the Series B Preferred Stock were converted into a total of 610,929 shares of common stock. During the third quarter of 2015, 28,170 shares of the Series B Preferred Stock were converted into a total of 697,207 shares of common stock. During the fourth quarter of 2015, 24,000 shares of the Series B Preferred Stock were converted into a total of 594,000 shares of common stock and 63,000 shares of the Series B Preferred Stock were repurchased with the proceeds of the December 2015 Offering. As of December 31, 2015, 7,146 shares of the Series B Preferred Stock were outstanding.

The terms and conditions of the Series B Preferred Stock were evaluated based on the guidance of the Derivatives and Hedging topic of the Codification to determine if the conversion feature was an embedded derivative requiring bifurcation. It was concluded that bifurcation was not required because the conversion feature was clearly and closely related to the Series B Preferred Stock. The conversion price at which shares of Series B Preferred Stock were convertible into shares of common stock was determined to be lower than the fair value of common stock at the date of entering into the agreement with the underwriter. This “in-the-money” beneficial conversion feature, or BCF, required separate recognition and measurement of its intrinsic value (i.e., the amount of the increase in value that holders of Series B Preferred Stock would realize upon conversion based on the value of the conversion shares on the date of the underwriting agreement). Because there was not a stated redemption date for the shares of Series B Preferred Stock, the BCF was recognized as a deemed dividend attributable to the Series B Preferred Stock and reflected as an adjustment in the calculation of earnings per share. The amount of the BCF totaled $4,140,446 for the May 2015 Offering.

The Company determined that equity classification was appropriate for the warrants in the December 2015 Offering and the May 2015 Offering following guidance in the Derivatives and Hedging topic of the Codification. In making this equity classification determination, the Company noted the warrants had no requirements to be settled in registered shares when exercised. The fair value of the 5 year warrants issued in connection with the December 2015 Offering was estimated to be $6.0 million on the offering date using date using a Black-Scholes model with the following assumptions: stock price of $1.98, exercise price of $2.30, expected volatility of 70.9%, risk free interest rate of 1.75%, expected term of five years, and no dividends. The fair value of the 1 year warrants issued in connection with the December 2015 Offering was estimated to be $2.2 million on the offering date using date using a Black-Scholes model with the following assumptions: stock price of $1.98, exercise price of $2.30, expected volatility of 65.7%, risk free interest rate of 0.65%, expected term of one year, and no dividends. The fair value of the warrants issued in connection with the May 2015 Offering was estimated to be $3.2 million on the offering date using utilizing quoted prices (unadjusted) in active markets. The relative fair values were recorded as equity.

In June 2014, the Company entered into a securities purchase agreement (the “2014 Offering”) for the issuance of (i) 166,150 shares of common stock at a price of $8.16 per share, (ii) 2,621.859 shares of Series A-3 Preferred Stock (the “Series A-3 Preferred Stock”) at a price of $1,000 per share, (iii) 4,022.357 shares of Series A-4 Preferred Stock (the “Series A-4 Preferred Stock,” and together with the Series A-3 Preferred Stock, the “Preferred Stock”) at a price of $1,000 per share, and (iv) five year warrants to purchase up to 980,392 shares of common stock with an exercise price of $8.16 per share. The 2014 Offering resulted in approximately $8.0 million in gross proceeds, before deducting expenses. Net proceeds from the 2014 Offering were approximately $7.9 million.

In the 2014 Offering, each share of Preferred Stock had a stated value of $1,000 and was convertible at the option of the holder into the number of shares of common stock determined by dividing the stated value by the conversion price of $8.16, which is subject to adjustment as provided in each applicable Certificate of Designation for the Preferred Stock. The Preferred Stock had no dividend rights, liquidation preference or other preferences over common stock and had no voting rights except as provided in each applicable Certificate of Designation for the Preferred Stock and as required by law. The 2014 Offering BCF measurement was limited by the transaction proceeds which had been allocated to the Preferred Stock. The BCF was recognized as a deemed dividend attributable to the Preferred Stock and reflected as an adjustment in the calculation of earnings per share in the quarter ended September 30, 2014. The amount of the BCF totaled $2,955,668 for the 2014 Offering.

The Series A-3 Preferred Stock was convertible into an aggregate of 321,306 shares of common stock and the Series A-4 Preferred Stock was convertible into an aggregate of 492,936 shares of common stock. During June 2014, 204 shares of the Series A-3 Preferred Stock were converted into a total of 25,000 shares of common stock. During July 2014, the remaining 2,417.859 shares of the Series A-3 Preferred Stock were converted into 296,306 shares of common stock. During October 2014, 408 shares of the Series A-4 Preferred Stock were converted into a total of 50,000 shares of common stock. During February 2015, 408 shares of the Series A-4 Preferred Stock were converted into a total of 50,000 shares of common stock. During May 2015, the remaining 3,206.357 shares of the Series A-4 Preferred Stock were repurchased by the Company at a price of $1,000 per share. Total consideration of $3.2 million for the repurchase of the Series A-4 convertible preferred stock and warrants was allocated to the convertible preferred stock and warrants based on their relative fair value. A BCF has been recognized as a return of capital from the preferred shareholders to the common shareholders attributable to the repurchase of 3,206.357 Series A-4 preferred stock and related beneficial embedded conversion feature, and is reflected as an adjustment in the calculation of earnings per share.

The Company continues to revalue unexercised warrants from the 2014 Offering at each reporting period over the life of the warrants using the Black-Scholes model and the changes in the fair value of the warrants were recognized in the Company's statement of operations. The warrants issued in connection with the 2014 Offering were within the scope of the Derivatives and Hedging topic of the Codification. This Codification topic requires issuers to classify as liabilities (or assets under certain circumstances) financial instruments which require an issuer to settle in registered shares. As the warrants are required to be settled in registered shares when exercised, the Company reflected the warrants as a liability in the balance sheet.

The fair value of the warrants issued in connection with the 2014 Offering was estimated to be $4.4 million on the offering date using a Black-Scholes model with the following assumptions: stock price of $8.00, exercise price of $8.16, expected volatility of 67.48%, risk free interest rate of 1.64%, expected term of five years, and no dividends. At December 31, 2015 587,456 warrants remain outstanding. They were revalued at December 31, 2015 in the amount of $0.2 million using the Black-Scholes model (see Note 7) and the liability was reflected in the December 31, 2015 balance sheet. The Company also continues to revalue warrants from its 2013 offering. At December 31, 2015, 264,332 warrants from its 2013 offering remain outstanding. They were revalued at December 31, 2015 in the amount of $0.1 million using the Black-Scholes model (see Note 7) and the liability was reflected in the December 31, 2015 balance sheet.

In 2015, 2014 and 2013, the Company issued shares of fully vested common stock in partial settlement of management incentive compensation. The 2015 issuance totaled 41,601 shares with a value of $281,757 reflecting the $6.72 closing price of the Company’s common stock as reported on the NASDAQ Capital Market on March 13, 2015. The 2014 issuance totaled 10,654 shares with a value of $104,400 reflecting the $9.80 closing price of the Company’s common stock as reported on the NASDAQ Capital Market on February 25, 2014. The 2013 issuance totaled 29,842 shares with a value of $285,300 reflecting the $9.56 NASDAQ Capital Market closing price on June 4, 2013.

As of December 31, 2015, the Company had 100,000,000 shares of common stock authorized and 4,047,332 shares issued and outstanding. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are not entitled to receive dividends unless declared by the Board of Directors.

At December 31, 2015, the Company has reserved authorized shares of common stock for future issuance as follows:


Warrants			15,816,393
Outstanding stock options			214,813
Possible future issuance under inducement plan			50,000
Possible future issuance under stock option plans			272,054
Possible future issuance under employee stock purchase plan			19,792
Total			16,373,052

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Paragraph 2
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Reverse Stock Split

12 Months Ended

Dec. 31, 2015

Reverse Stock Split [Abstract]

Reverse Stock Split

13. Reverse Stock Split

The Company’s common stock is quoted on the NASDAQ Capital Market under the symbol “NURO.” One of the requirements for continued listing on the NASDAQ Capital Market is maintenance of a minimum closing bid price of $1.00 per share. Because the Company’s common stock had been trading below a price of $1.00 per share, and was subject to delisting from The NASDAQ Stock Market LLC, or NASDAQ as a result, on December 1, 2015, the Company filed a Certificate of Amendment to its Restated Certificate of Incorporation, as amended, with the Secretary of State of the State of Delaware, to effect a 1-for-4 reverse stock split of its common stock, or the Reverse Stock Split. This action had previously been approved by the Company’s stockholders at the Company’s special meeting held on October 30, 2015. As a result of the Reverse Stock Split, every four shares of the Company’s pre-reverse split common stock were combined and reclassified into one share of its common stock. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise would have been entitled to receive a fractional share in connection with the Reverse Stock Split received a cash payment in lieu thereof. The par value and other terms of the common stock were not affected by the Reverse Stock Split.

The Company’s shares outstanding immediately prior to the Reverse Stock Split totaled 13,785,239, which were adjusted to 3,446,274 shares outstanding as a result of the Reverse Stock Split. The Company’s common stock began trading at its post-Reverse Stock Split price at the beginning of trading on December 2, 2015. Share, per share, and stock option amounts for all periods presented within the financial statements contained in the Annual Report on Form 10-K including the December 31, 2014 Balance Sheet amounts for common stock and additional paid-in capital have been retroactively adjusted to reflect the Reverse Stock Split.

On December 16, 2015, the Company received a letter from NASDAQ indicating that it had regained compliance with the minimum bid price requirement under NASDAQ Listing Rule 5550(a)(2) for continued listing on The NASDAQ Capital Market. The Company’s common stock continues to be listed on NASDAQ.

Management Retention and Incentive Plan

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Management Retention and Incentive Plan

14. Management Retention and Incentive Plan

The Company has adopted the Management Retention and Incentive Plan (the “Plan”), under which a portion of the consideration payable upon a change in control transaction, as defined in the Plan and its amendments, would be paid in cash to certain executive officers and key employees and recorded as compensation expense within the Statement of Operations during the period in which the change of control transaction occurs. The Plan is structured to work in conjunction with, and not replace, the Company’s other incentive programs and is designed to provide market-based incentives which will be reduced over time by any future equity grants to participants.

NeuroMetrix, Inc.

Schedule II — Valuation and Qualifying Accounts


Description	Balance at Beginning of Period		Charged to costs and expenses		Charged to other accounts		Recoveries/ (Deductions)			Balance at End of Period
December 31, 2015
Allowance for Doubtful Accounts	$	38,000		—		—		(13,000	)	$	25,000
Sales Returns Reserve		1,966		—		487,782		(424,637	)		65,111
Deferred Tax Asset Valuation Allowance		38,565,925		5,342,672		—		(248,562	)⁽²⁾		43,660,035
December 31, 2014
Allowance for Doubtful Accounts	$	35,000	$	26,042		—	$	(23,042	)	$	38,000
Sales Returns Reserve		895		—		49,114		(48,043	)		1,966
Deferred Tax Asset Valuation Allowance		36,108,231		3,280,605		—		(822,911	)⁽²⁾		38,565,925
December 31, 2013
Allowance for Doubtful Accounts	$	130,000	$	111,296	$	—	$	(206,296	)⁽¹⁾	$	35,000
Sales Returns Reserve		21,616		—		38,278		(58,999	)⁽¹⁾		895
Deferred Tax Asset Valuation Allowance		34,347,467		2,976,809		—		(1,216,045	)⁽²⁾		36,108,231

(1)	Net write-offs.

(2)	Expiration of Federal and State Net Operating Loss Carryforwards and other reductions.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Use of Estimates and Assumptions

Cash and Cash Equivalents

Concentrations of Credit Risk

Research and Development

Product Warranty Costs

Fixed Assets and Long-Lived Assets

Accounting for Stock-Based Compensation

Net Loss per Common Share


	Years Ended December 31,
	2015		2014		2013
Options		208,135		125,207		40,348
Warrants		3,222,071		609,084		513,933
Unvested restricted stock		80		1,122		5,597
Convertible preferred stock		2,264,086		228,143		—
Total		5,694,372		963,556		559,878

Net loss per common share applicable to common stockholders, basic and diluted was determined as follows:


	Years Ended December 31,
	2015			2014			2013
Net loss	$	(9,187,348	)	$	(7,766,222	)	$	(8,019,137	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		(4,140,446	)		(2,955,668	)		(766,872	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(8,332,212	)		—			—
Return of capital to common shareholders attributable to the repurchase of preferred shares and related embedded beneficial conversion feature		589,751			—			—
Net loss applicable to common stockholders	$	(21,070,255	)	$	(10,721,890	)	$	(8,786,009	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.75	)	$	(6.15	)	$	(12.28	)
Weighted average number of common shares outstanding, basic and diluted		2,719,285			1,743,494			715,524

Advertising and Promotional Costs

Advertising and promotional costs are expensed as incurred. Advertising and promotion expense was $2,499,000, $481,000, and $151,000, in 2015, 2014, and 2013, respectively.

Accumulated Other Comprehensive Items

For 2015, 2014, and 2013, the Company had no components of other comprehensive income or loss other than net loss.

Segments

Risks and Uncertainties

Recently Issued or Adopted Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Potentially Calculation of Diluted Net Income Per Common

the following potentially dilutive weighted average number of common stock equivalents were excluded from the calculation of diluted net loss per common share because their effect was anti-dilutive for each of the periods presented:


	Years Ended December 31,
	2015		2014		2013
Options		208,135		125,207		40,348
Warrants		3,222,071		609,084		513,933
Unvested restricted stock		80		1,122		5,597
Convertible preferred stock		2,264,086		228,143		—
Total		5,694,372		963,556		559,878

Schedule of Earnings Per Share, Basic and Diluted

Net loss per common share applicable to common stockholders, basic and diluted was determined as follows:


	Years Ended December 31,
	2015			2014			2013
Net loss	$	(9,187,348	)	$	(7,766,222	)	$	(8,019,137	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		(4,140,446	)		(2,955,668	)		(766,872	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(8,332,212	)		—			—
Return of capital to common shareholders attributable to the repurchase of preferred shares and related embedded beneficial conversion feature		589,751			—			—
Net loss applicable to common stockholders	$	(21,070,255	)	$	(10,721,890	)	$	(8,786,009	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.75	)	$	(6.15	)	$	(12.28	)
Weighted average number of common shares outstanding, basic and diluted		2,719,285			1,743,494			715,524

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Share-based Compensation [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions


	Years Ended December 31,
	2015			2014			2013
Risk-free interest rate		1.3 – 1.7%			1.4 – 1.8%			1.4 – 1.7%
Expected dividend yield		—			—			—
Expected option term		5 years			5 years			5 years
Volatility		70.0	%		70.0	%		70.0	%

Schedule of Share-based Compensation, Activity

A summary of option activity for the year ended December 31, 2015 is presented below:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2014		190,481		$	20.67
Granted		31,376			5.07
Exercised		—			—
Forfeited		(7,044	)		8.05
Expired		—			—
Outstanding at December 31, 2015		214,813			18.81		8.3	$	0
Vested or expected to vest at December 31, 2015		204,310			19.45		7.9		0
Exercisable at December 31, 2015		118,822			28.67		8.3		0

Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock Units, Vested and Expected to Vest

A summary of restricted stock activity for the year ended December 31, 2015 is presented below:


	Restricted Shares			Weighted Average Grant Date Fair Value
Restricted shares at December 31, 2014		208		$	7.60
Granted		—			—
Vested		(208	)		(7.60	)
Canceled		—			—
Restricted shares at December 31, 2015		—		$	—

Fixed Assets (Tables)

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Fixed Assets

Fixed assets consist of the following:

	Estimated Useful Life (Years)			December 31,
	Estimated Useful Life (Years)			2015			2014
Construction in process				$	—			182,755
Computer and laboratory equipment		3			1,698,390		$	1,782,330
Furniture and equipment		3			319,046			109,617
Production equipment		7			864,287			745,596
Leasehold improvements			*		117,994			7,268
					2,999,717			2,827,566
Less – accumulated depreciation					(2,316,183	)		(2,516,046	)
				$	683,534		$	311,520

Lesser of life of lease or estimated useful life.

Accrued Compensation and Expenses (Tables)

12 Months Ended

Dec. 31, 2015

Payables and Accruals [Abstract]

Accrued Liabilities Restructuring Actions


	December 31,
	2015			2014
Balance – beginning	$	148,921		$	110,608
Accrual for severance		—			302,758
Severance payments made		(148,921	)		(264,445	)
Balance – ending	$	—		$	148,921

Accrued Compensation and Expenses

Accrued expenses consist of the following for the years ended December 31, 2015 and 2014:

	December 31,
	2015		2014
Technology fees	$	450,000	$	450,000
Professional services		336,229		257,024
Consulting fees		92,000		173,759
Clinical study obligations		—		74,000
Sales taxes		56,284		34,206
Personnel related obligations		15,548		37,761
Federal excise tax		1,023		25,989
Other		104,399		212,137
	$	1,055,483	$	1,264,876

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Effective Income Tax Rate Reconciliation

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2015, 2014, and 2013.


	Years Ended December 31,
	2015			2014			2013
Federal tax provision (benefit) rate		(34.0	)%		(34.0	)%		(34.0	)%
State tax provision, net of federal provision		(8.5	)		(7.0	)		(4.8	)
Permanent items		(14.5	)		(3.6	)		3.4
Federal research and development credits		(1.3	)		(1.0	)		(1.7	)
Expiration of tax attribute		—			10.9			—
Valuation allowance		58.3			34.7			37.1
Effective income tax rate		—	%		—	%		—	%

Deferred Tax Assets and Liabilities

The Company’s deferred tax assets consist of the following:


	December 31,
	2015			2014
Deferred tax assets:
Net operating loss carryforwards	$	40,397,318		$	35,449,695
Research and development credit carryforwards		2,005,741			1,855,586
Accrued expenses		704,957			657,132
Stock-based compensation		538,321			590,006
Other		13,698			13,506
Total gross deferred tax assets		43,660,035			38,565,925
Valuation allowance		(43,660,035	)		(38,565,925	)
Net deferred tax assets	$	—		$	—

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair values determined by Level 2 inputs utilize data points that are observable such as quoted prices, interest rates, and yield curves. Fair values determined by Level 3 inputs are unobservable data points for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability.


	December 31, 2015		Fair Value Measurements at December 31, 2015 Using
	December 31, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	1,865,498	$	1,865,498	$	—	$	—
Total	$	1,865,498	$	1,865,498	$	—	$	—
Liabilities:
Common stock warrants	$	280,303	$	—	$	—	$	280,303
Total	$	280,303	$	—	$	—	$	280,303

	December 31, 2014		Fair Value Measurements at December 31, 2014 Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	4,107,478	$	4,107,478	$	—	$	—
Total	$	4,107,478	$	4,107,478	$	—	$	—
Liabilities:
Common stock warrants	$	5,307,307	$	—	$	—	$	5,307,307
Total	$	5,307,307	$	—	$	—	$	5,307,307

Black-Scholes Inputs to Warrant Liability Valuation

The assumptions used may change as the underlying sources of these assumptions and market conditions change. Based on the Black-Scholes model, the Company recorded a common stock warrants liability of $0.3 million at December 31, 2015.


	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2015
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	1.98	$	8.16		73.39	%		1.42	%		3yr 6mo		none
2013 Offering	$	1.98	$	8.00		70.42	%		1.17	%		2yr 5mo		none

	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2014
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	7.80	$	8.16		71.11	%		1.51	%		4yr 6mo		none
2013 Offering	$	7.80	$	8.00		75.71	%		1.24	%		3yr 5mo		none

Fair Value, Liabilities Measured on Recurring Basis

The following table provides a summary of changes in the fair value of the Company’s Level 3 financial liabilities between December 31, 2013 and December 31, 2015.


	2014 Offering			2013 Offering			Total
Balance at December 31, 2013	$	—		$	1,938,603		$	1,938,603
Initial fair value of warrants at issuance in June 2014		4,418,824			—			4,418,824
Change in fair value of warrant liability		(185,095	)		(865,000	)		(1,050,095	)
Balance at December 31, 2014	$	4,233,729		$	1,073,603		$	5,307,332
Repurchase of warrants in conjunction with public offering		(943,423	)		—			(943,423	)
Change in fair value of warrant liability		(3,062,314	)		(1,021,292	)		(4,083,606	)
Balance at December 31, 2015	$	227,992		$	52,311		$	280,303

Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Organization And Basis Of Presentation [Line Items]
Proceeds from issuance or sale of equity, total	$ 16,800,000
Retained Earnings (Accumulated Deficit), Total	(163,565,650)	$ (154,378,302)
Cash and Cash Equivalents, at Carrying Value, Total	12,462,872	$ 9,221,985	$ 9,195,753	$ 8,699,478
Temporary Equity, Accretion to Redemption Value	$ 19,000,000

Anti-dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Income Per Common Share (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	5,694,372	963,556	559,878
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	208,135	125,207	40,348
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	3,222,071	609,084	513,933
Unvested Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	80	1,122	5,597
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	2,264,086	228,143	0

Determination of Net Loss Per Common Share (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Determination of net loss per common share [Line Items]
Net loss	$ (9,187,348)	$ (7,766,222)	$ (8,019,137)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features	(4,140,446)	(2,955,668)	(766,872)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications	(8,332,212)	0	0
Return of capital to common shareholders attributable to the repurchase of preferred shares and related embedded beneficial conversion feature	589,751	0	0
Net loss applicable to common stockholders	$ (21,070,255)	$ (10,721,890)	$ (8,786,009)
Net loss per common share applicable to common stockholders, basic and diluted	$ (7.75)	$ (6.15)	$ (12.28)
Weighted average number of common shares outstanding, basic and diluted	2,719,285	1,743,494	715,524

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Sales Revenue Goods Net Percentage From Foreign Country	19.00%	19.00%	16.00%
Standard Product Warranty Accrual, Total	$ 10,484	$ 1,784
Marketing and Advertising Expense, Total	2,499,000	$ 481,000	$ 151,000
Deferred Tax Liabilities, Gross, Noncurrent	$ 45,000
Customer One [Member] \| Accounts Receivable [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration Risk, Percentage	46.00%
Customer One [Member] \| Sales Revenue, Net [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration Risk, Percentage	12.00%	30.00%	10.00%

Weighted Average Grant-Date Fair Value Used in the Calculation of Stock-Based Compensation Expense (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Expected dividend yield	0.00%	0.00%	0.00%
Expected option term	5 years	5 years	5 years
Volatility	70.00%	70.00%	70.00%
Maximum [Member]
Risk-free interest rate	1.70%	1.80%	1.70%
Minimum [Member]
Risk-free interest rate	1.30%	1.40%	1.40%

Summary of option activity (Detail)	12 Months Ended
Summary of option activity (Detail)	Dec. 31, 2015 USD ($) $ / shares shares
Summary Of Option Activity [Line Items]
Number of Outstanding at December 31, 2014 \| shares	190,481
Number of Options Granted \| shares	31,376
Number of Options Exercised \| shares	0
Number of Options Forfeited \| shares	(7,044)
Number of Options Expired \| shares	0
Number of Options Outstanding at December 31, 2015 \| shares	214,813
Number of Options, Vested or expected to vest at December 31, 2015 \| shares	204,310
Number of Options, Exercisable at December 31, 2015 \| shares	118,822
Weighted Average Exercise Price Outstanding at December 31, 2014 \| $ / shares	$ 20.67
Weighted Average Exercise Price Granted \| $ / shares	5.07
Weighted Average Exercise Price Exercised \| $ / shares	0
Weighted Average Exercise Price Forfeited \| $ / shares	8.05
Weighted Average Exercise Price, Expired \| $ / shares	0
Weighted Average Exercise Price Outstanding at December 31, 2015 \| $ / shares	18.81
Weighted Average Exercise Price, Vested or expected to vest at December 31, 2015 \| $ / shares	19.45
Weighted Average Exercise Price, Exercisable at December 31, 2015 \| $ / shares	$ 28.67
Weighted Average Remaining Contractual Life (in years), Outstanding at December 31, 2015	8 years 3 months 18 days
Weighted Average Remaining Contractual Life (in years), Vested or expected to vest at December 31, 2015	7 years 10 months 24 days
Weighted Average Remaining Contractual Life (in years), Exercisable at December 31, 2015	8 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding at December 31, 2015 \| $	$ 0
Aggregate Intrinsic Value, Vested or expected to vest at December 31, 2015 \| $	0
Aggregate Intrinsic Value, Exercisable at December 31, 2015 \| $	$ 0

Summary of restricted stock activity (Detail)	12 Months Ended
Summary of restricted stock activity (Detail)	Dec. 31, 2015 $ / shares shares
Summary Of Restricted Stock Activity [Line Items]
Restricted shares at December 31, 2014 \| shares	208
Restricted Shares, Granted \| shares	0
Restricted Shares, Vested \| shares	(208)
Restricted Shares, Canceled \| shares	0
Restricted shares at December 31, 2015 \| shares	0
Weighted Average Grant Date Fair Value Restricted shares at December 31, 2014 \| $ / shares	$ 7.60
Weighted Average Grant Date Fair Value Restricted Shares, Granted \| $ / shares	0
Weighted Average Grant Date Fair Value Restricted Shares, Vested \| $ / shares	(7.60)
Weighted Average Grant Date Fair Value Restricted Shares, Canceled \| $ / shares	0
Weighted Average Grant Date Fair Value Restricted shares at December 31, 2015 \| $ / shares	$ 0

Stock-Based Compensation - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended
	May. 05, 2015	May. 31, 2010	Jun. 30, 2004	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	212,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				214,813	190,481
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance				$ 18.81	$ 20.67
Common Stock, Shares, Issued				4,047,332	2,038,151
Common Stock, Shares, Outstanding				4,047,332	2,038,151
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 2.95	$ 4.24	$ 4.08
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value				$ 0	$ 0	$ 0
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total				$ 288,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares, Beginning Balance				214,813
Share Based Compensation Arrangement By Share Based Payment Award Options Nonvested Weighted Average Price Per Shares				$ 11.18
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				2 years 1 month 6 days
Stock Issued During Period, Shares, Restricted Stock Award, Gross						500
Number Of Shares Authorized To With Holding In Lieu Of Paying With Holding Taxes				0	0	1,054
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options, Total				$ 38,000	$ 24,000	$ 26,000
Allocated Share-based Compensation Expense				$ 302,000	$ 290,000	$ 246,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Combined Voting Power Of All Classes Of Stock				10.00%
Percentage Of Fair Market Value				110.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				3 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				4 years
Two Zero Zero Four Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period				10 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				531,570
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period				94,703
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				164,813
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance				$ 22.23
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				272,054
Two Zero Zero Nine Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				100,000
Common Stock, Shares, Issued				50,000
Common Stock, Shares, Outstanding				50,000
Two Zero Zero Four Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			2,604
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights			All of the Companys employees who had been employed by the Company for at least 60 days and whose customary employment is for more than 20 hours per week and for more than five months in any calendar year were eligible to participate and any employee who owned 5% or more of the voting power or value of the Companys stock was not eligible to participate.
Two Zero One Zero Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		1,736
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period				15,443	3,681
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				19,792
Percentage Of Fair Market Value				85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights		1,736 shares, (ii) 1 percent of the shares of common stock outstanding on the last day of the immediately preceding fiscal year, or (iii) such lesser number of shares as is determined by the Board. At the Companys Annual Meeting of Stockholders held on May 14, 2012, the stockholders of the Company approved the Companys Amended and Restated 2010 Employee Stock Purchase Plan (the Amended and Restated 2010 ESPP), which, among other things, increased the number of shares of the Companys common stock authorized for issuance thereunder by 4,167 shares. All of the Companys full-time employees and certain part-time employees are eligible to participate in the Amended and Restated 2010 ESPP. For part-time employees to be eligible, they must have customary employment of more than five months in any calendar year and more than 20 hours per week. Employees who, after exercising their rights to purchase shares under the Amended and Restated 2010 ESPP, would own shares representing 5% or more of the voting power of the Companys common stock, are ineligible to participate.
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate				10.00%
Withholdings Payment Period				6 months

Inventories (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Line Items]
Purchased components	$ 432,437	$ 209,426
Finished goods on consignment	39,784	0
Finished goods	616,863	470,314
Inventories	$ 1,089,084	$ 679,740

Fixed Assets (Details) - USD ($)

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Less - accumulated depreciation

$ 2,999,717

$ 2,827,566

(2,316,183)

(2,516,046)

Fixed assets, net

683,534

311,520

Construction in Progress [Member]

Computer And Laboratory Equipment [Member]

182,755

$ 1,698,390

1,782,330

Furniture And Equipment [Member]

3 years

$ 319,046

109,617

Production Equipment [Member]

3 years

$ 864,287

745,596

Leasehold Improvements [Member]

7 years

$ 117,994

$ 7,268