Schedule II — Valuation and Qualifying Accounts

Description of Business and Basis of Presentation

1. Description of Business and Basis of Presentation

NeuroMetrix, or the Company, is a commercial stage, innovation driven healthcare company combining bioelectrical and digital medicine to address chronic health conditions including chronic pain, sleep disorders, and diabetes. The company’s lead product is Quell, an over-the-counter wearable therapeutic device for chronic pain. Quell is integrated into a digital health platform that helps patients optimize their therapy and decrease the impact of chronic pain on their quality of life. The company also markets DPNCheck®, a rapid point-of-care test for diabetic neuropathy, which is the most common long-term complication of Type 2 diabetes. The company maintains an active research effort and has several pipeline programs. The company is located in Waltham, Massachusetts and was founded as a spinoff from the Harvard-MIT Division of Health Sciences and Technology in 1996.

During 2016 the Company completed an equity offering which is detailed in Note 12 to the financial statements. This financing resulted in proceeds of approximately $7.5 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 $6.7 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, 2016, the Company had an accumulated deficit of $178.5 million. The Company held cash and cash equivalents of $3.9 million as of December 31, 2016. The Company believes that these resources, cash proceeds from a $7 million equity offering, the first tranche of $4.0 million which closed on January 5, 2017, and a second tranche of $3.0 million which is subject to shareholder approval and expected to close late in the first quarter of 2017 (see footnote 15), and the cash to be generated from expected product sales will be sufficient to meet its projected operating requirements into the fourth quarter of 2017. 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 fourth quarter of 2017 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.

The Company received notice from NASDAQ that it was not in compliance with the $1.00 per share minimum bid requirement for continued listing on the exchange. NASDAQ has provided a grace period until August 1, 2017 for the Company to regain compliance, to appeal the determination or to risk being delisted from the NASDAQ Capital Market.

Certain amounts within the prior year balance sheet have been reclassified to conform to current year presentation.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

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, 2016 and 2015, two customers accounted for 41% of accounts receivable and a different customer accounted for 46% of accounts receivable, respectively. For the year ended December 31, 2016 no customer accounted for more than 10% of revenue. For the years ended December 31, 2015 and 2014, one customer accounted for 12% and 30% 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.

Fair Value

The carrying amounts of the Company’s accounts receivable, accounts payable, and accrued expenses approximate their fair value at December 31, 2016 and 2015 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 are generally recognized upon shipment, assuming all other revenue recognition criteria have been met. Revenue associated with shipments made to distributors who have the right to return any unsold product is recognized once the product is sold by the distributor to the end customer (i.e. under a sell-through model), assuming all other revenue recognition criteria have been met. Cash received prior to all the conditions for revenue recognition being met is recorded as deferred revenue.

As of December 31, 2016 the total value of shipments made to sell-through distributors but not yet sold through to end customers totaled $1,247,545. Of this total, $619,309 was recorded as a reduction to accounts receivable and $628,236 was recorded in deferred revenue, as cash had been received. As of December 31, 2015, the total value of shipments that had been made to sell-through distributors but have not yet been sold through to end customers totaled $489,467. Of this total, $262,295 was recorded as a reduction to accounts receivable and $227,172 was recorded in deferred revenue, as cash had been received. Related costs of goods sold of $910,595 and $378,440 have been deferred and recorded in prepaid expenses and other current assets as of December 31, 2016 and 2015, respectively.

Revenue recognition involves judgments, including assessments of expected returns from customers who have the right to return product for any reason under 30-day or 60-day rights of return. Where the Company can reasonably estimate future returns, it recognizes revenues and records as a reduction of revenue a provision for estimated returns. The Company analyzes various factors, including its historical product returns in arriving at this judgment. Changes in judgments or estimates could materially impact the timing and amount of revenues and costs recognized. The provision for expected returns recorded as accrued expense was $488,200 and $65,111 as of December 31, 2016 and 2015, respectively.

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 $45,879 and $10,484 at December 31, 2016 and 2015, 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,
	2016		2015		2014
Options		421,798		208,135		125,207
Warrants		22,790,327		3,222,071		609,084
Unvested restricted stock		—		80		1,122
Convertible preferred stock		8,603,028		2,264,086		228,143
Total		31,815,153		5,694,372		963,556

The Beneficial Conversion Feature, or BCF, recorded in the 2016, 2015 and 2014 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,
	2016			2015			2014
Net loss	$	(14,913,151	)	$	(9,187,348	)	$	(7,766,222	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		—			(4,140,446	)		(2,955,668	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(19,846,377	)		(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	$	(34,759,528	)	$	(21,070,255	)	$	(10,721,890	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.28	)	$	(7.75	)	$	(6.15	)
Weighted average number of common shares outstanding, basic and diluted		4,777,037			2,719,285			1,743,494

Advertising and Promotional Costs

Advertising and promotional costs are expensed as incurred. Advertising and promotion expense was approximately $6,311,000, $2,499,000, and $481,000, in 2016, 2015, and 2014, respectively.

Accumulated Other Comprehensive Items

For 2016, 2015, and 2014, 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 2016, 2015, and 2014 were located at or derived from operations in the United States. Revenues from sales outside the United States accounted for approximately 12%, 19%, and 19% of total revenues in 2016, 2015 and 2014, respectively.

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 February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 requires that lessees will need to recognize virtually all of their leases on the balance sheet, by recording a right-of-use asset and lease liability. The provisions of this guidance are effective for annual periods beginning after December 31, 2018, and for interim periods therein. The Company is in the process of evaluating the new standard and assessing the impact, if any, ASU 2016-02 will have on the Company’s Financial Statements.

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. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers, which delayed the effective date of the new standard from January 1, 2017 to January 1, 2018. 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. In March 2016, the FASB issued ASU No. 2016-08, Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net), which clarifies the implementation guidance on principal versus agent considerations. The Company is in the process of evaluating the new standard and assessing the impact, if any, ASU 2014-09 will have on the Company’s Financial Statements or which adoption method will be used.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2016

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 2016. At the Annual Meeting of Stockholders held on May 3, 2016, the stockholders of the Company approved the Company’s Eighth 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 500,000 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, 2016, 1,031,570 shares of common stock were authorized for issuance under the 2004 Stock Plan, of which 272,786 shares had been issued, 732,364 shares were subject to outstanding options at a weighted average exercise price of $4.37 per share and 26,420 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, 2016, 100,000 shares of common stock were authorized for issuance under the 2009 Inducement Plan, of which 50,000 shares were subject to outstanding options at a weighted average exercise price of $7.52 per share and 50,000 shares were available for future grant.

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 3, 2016, the stockholders of the Company approved the Company’s Third 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 100,000 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, 2016 and 2015 the Company issued 35,002 and 15,443 shares of its common stock, respectively, under the Amended and Restated 2010 ESPP. As of December 31, 2016, there were 88,957 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, 2016, 2015, and 2014 is calculated using the following assumptions:

	Years Ended December 31,
	2016			2015			2014
Risk-free interest rate		0.9 – 1.8%			1.3 – 1.7%			1.4 – 1.8%
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, 2016 is presented below:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2015		214,813		$	18.81
Granted		575,500			1.48
Exercised		—			—
Forfeited		(7,688	)		5.67
Expired		(261	)		4,857.94
Outstanding at December 31, 2016		782,364			4.57		9.0	$	0
Vested or expected to vest at December 31, 2016		679,013			5.02		8.9		0
Exercisable at December 31, 2016		168,229			14.72		7.1		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, 2016, 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, 2016.

The weighted average per share grant-date fair values of options granted during 2016, 2015, and 2014 was $0.85, $2.95, and $4.24, respectively.

The aggregate intrinsic value of options issued or exercised during 2016, 2015, and 2014 was $0.

Total unrecognized stock-based compensation costs related to non-vested stock options was $487,922, which related to 782,364 shares with a per share weighted fair value of $4.57 as of December 31, 2016. This unrecognized cost is expected to be recognized over a weighted average period of approximately 3.2 years.

Cash received from option exercises and purchases under the 2004 ESPP and the 2010 ESPP for the years 2016, 2015, and 2014, was $29,000, $38,000, and $24,000, 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 $225,408, $302,415, and $289,873 for 2016, 2015, and 2014, respectively.

Property, Plant and Equipment [Abstract]

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Fixed Assets

12 Months Ended

Dec. 31, 2016

Fixed Assets

5. Fixed Assets

Fixed assets consist of the following:


	Estimated Useful Life (Years)			December 31,
	Estimated Useful Life (Years)			2016			2015
Computer and laboratory equipment		3		$	1,724,819		$	1,698,390
Furniture and equipment		3			319,046			319,046
Production equipment		7			938,357			864,287
Leasehold improvements			*		117,994			117,994
					3,100,216			2,999,717
Less – accumulated depreciation					(2,567,510	)		(2,316,183	)
				$	532,706		$	683,534

Lesser of life of lease or estimated useful life.

Depreciation expense was $251,327, $222,592, and $145,100 for 2016, 2015, and 2014, respectively.

Income Taxes

12 Months Ended

Dec. 31, 2016

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, 2016, 2015, and 2014.

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2016, 2015, and 2014.

	Years Ended December 31,
	2016			2015			2014
Federal tax provision (benefit) rate		(34.0	)%		(34.0	)%		(34.0	)%
State tax provision, net of federal provision		(4.2	)		(8.5	)		(7.0	)
Permanent items		(0.2	)		(14.5	)		(3.6	)
Federal research and development credits		(0.9	)		(1.3	)		(1.0	)
Expiration of tax attribute		—			—			10.9
Valuation allowance		39.3			58.3			34.7
Effective income tax rate		—	%		—	%		—	%

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

	December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	45,759,780		$	40,397,318
Research and development credit carryforwards		2,180,700			2,005,741
Accrued expenses		752,866			704,957
Stock-based compensation		566,487			538,321
Other		14,321			13,698
Total gross deferred tax assets		49,274,154			43,660,035
Valuation allowance		(49,274,154	)		(43,660,035	)
Net deferred tax assets	$	—		$	—

At December 31, 2016, the Company has federal and state net operating loss carryforwards (“NOL”) of $132.9 million and $43.2 million, respectively, as well as federal and state tax credits of $1.4 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 NOLs begin to expire in 2019 and the state NOLs 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 $49.3 million and $43.7 million has been established at December 31, 2016 and 2015, 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. The Company has not recorded any amounts for unrecognized tax benefits as of December 31, 2016 or 2015. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending income tax examinations. The Company’s tax years are still open under statute from December 31, 2013 to the present. Earlier years may be examined to the extent that tax credit or net operating loss carryforwards are used in future periods. The Company’s policy is to record interest and penalties related to income taxes as part of its income tax provision.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

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, 2016 are as follows:

2017		530,674
2018		542,645
2019		547,018
2020		475,408
2021		487,379
2022		81,562
Total minimum lease payments	$	2,664,686

Total recorded rent expense was $581,928, $679,026, and $638,679, for 2016, 2015, and 2014, respectively. The Company records rent expense on its facility lease on a straight-line basis over the lease term.

Other Commitments

At December 31, 2016, other commitments, comprised of purchase orders, totaled approximately $1,699,823.

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

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, 2016		Fair Value Measurements at December 31, 2016 Using
	December 31, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	833,831	$	833,831	$	—	$	—
Total	$	833,831	$	833,831	$	—	$	—
Liabilities:
Common stock warrants	$	4,641	$	—	$	—	$	4,641
Total	$	4,641	$	—	$	—	$	4,641

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, 2016 using the Black-Scholes model, which is based on Level 3 inputs. As of December 31, 2016, 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 $4,641 at December 31, 2016.

	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2016
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	0.74	$	8.16		64.19	%		1.33	%		2yr 6mo		none
2013 Offering	$	0.74	$	8.00		71.61	%		0.99	%		1yr 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, 2014 and December 31, 2016.

	2014 Offering			2013 Offering			Total
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
Change in fair value of warrant liability		(223,880	)		(51,782	)		(275,662	)
Balance at December 31, 2016	$	4,112		$	529		$	4,641

	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 $280,303 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

Compensation and Retirement Disclosure [Abstract]

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, 2016

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 2016, 2015 and 2014 the Company made no contributions to the plan.

Credit Facility

12 Months Ended

Dec. 31, 2016

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, 2016 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 December 29, 2016, and extended until January 15, 2018. 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. 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, 2016, the Company was in compliance with these covenants and had not borrowed any funds under the Credit Facility. However, $896,571 of the amount under the Credit Facility is restricted to support letters of credit issued in favor of our facilities landlords and a materials component supplier. Consequently, the amount available for borrowing under the Credit Facility as of December 31, 2016 was approximately $1.6 million.

Stockholders' Equity

12 Months Ended

Dec. 31, 2016

Stockholders' Equity Note [Abstract]

Stockholders' Equity

12. Stockholders’ Equity

Preferred stock and convertible preferred stock consist of the following:

	December 31,
	2016		2015
Preferred stock, $0.001 par value; 5,000,000 shares authorized at December 31, 2016 and 2015; no shares issued and outstanding at December 31, 2016 and 2015	$	—	$	—
Series B convertible preferred stock, $0.001 par value, 147,000 shares designated at December 31, 2016 and 2015, and 500 and 7,146 shares issued and outstanding at December 31, 2016 and 2015, respectively		1		7
Series C convertible preferred stock, $0.001 par value, 13,800 shares designated at December 31, 2016 and 2015, and zero and 13,800 shares issued and outstanding at December 31, 2016 and 2015, respectively		—		14
Series D convertible preferred stock, $0.001 par value, 21,300 and zero shares designated at December 31, 2016 and 2015, respectively, and 17,202.65 and zero shares issued and outstanding at December 31, 2016 and 2015, respectively		17		—

Private and Public Offerings of Common Stock and Warrants

In June 2016, the Company completed a private equity offering with one institutional investor (the “Investor”) and issued (i) 21,300 shares of Series D convertible preferred stock (the “Series D Preferred Stock”) at a price of $1,000 per share, and (ii) warrants to purchase up to 11,800,554 shares of common stock, par value $0.0001 per share (the “Common Stock”), at an exercise price of $1.69 per share (the “June 2016 Offering”). As a part of this offering, the Company redeemed 13,800 shares of Series C convertible preferred stock (the “Series C Preferred Stock”) issued in the December 2015 Offering that were held by the Investor. Accordingly, the June 2016 Offering resulted in proceeds of $7.5 million. After underwriting discounts, commission and expenses, net proceeds of the June 2016 Offering were $6.7 million.

Each share of Series D 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 $1.805, which is subject to adjustment as provided in the Certificate of Designation for the Series D Preferred Stock. The Series D 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 D Preferred Stock and as required by law.

The June 2016 Offering was accounted for as a modification of the Investor’s Series C Preferred Stock. Under the modification model, a deemed dividend was recognized within retained earnings which represented the fair value of consideration transferred plus the fair value of repurchased Series C Preferred Stock, less the fair value of the newly issued Series D Preferred Stock and warrants. The amount of the deemed dividend totaled $19.8 million. During 2016, 4,097.35 shares of the Series D Preferred Stock were converted into a total of 2,270,000 shares of common stock. As of December 31, 2016, 17,202.65 shares of Series D Preferred Stock remained outstanding.

In December 2015, the Company completed a private equity offering with the Investor 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, 2016, zero 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. 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 2015, 76,854 shares of the Series B Preferred Stock were converted into a total of 1,902,137 shares of common stock. 63,000 shares of the Series B Preferred Stock were repurchased with the proceeds of the December 2015 Offering. During 2016, 6,646 shares of the Series B Preferred Stock were converted into a total of 164,488 shares of common stock. As of December 31, 2016, 500 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 June 2016, 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 June 2016 Offering was estimated to be $14.6 million on the offering date using date using a Black-Scholes model with the following assumptions: stock price of $1.99, exercise price of $1.69, expected volatility of 71.5%, risk free interest rate of 1.23%, expected term of five years, and no dividends. 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 2016, 2015 and 2014, the Company issued shares of fully vested common stock in partial settlement of management incentive compensation. The 2016 issuance totaled 178,079 shares with a value of $318,761 reflecting the $1.79 closing price of the Company’s common stock as reported on the NASDAQ Capital Market on March 9, 2016. 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.

As of December 31, 2016, the Company had 100,000,000 shares of common stock authorized and 6,694,901 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, 2016, the Company has reserved authorized shares of common stock for future issuance as follows:

Warrants			28,206,975
Outstanding stock options			782,364
Possible future issuance under inducement plan			50,000
Possible future issuance under stock option plans			26,420
Possible future issuance under employee stock purchase plan			88,957
Total			29,154,716

Valuation and Qualifying Accounts [Abstract]

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

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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Reverse Stock Split

12 Months Ended

Dec. 31, 2016

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.

Subsequent Event

12 Months Ended

Dec. 31, 2016

Subsequent Events [Abstract]

Subsequent Event

15. Subsequent Event

In January 2017, the Company completed the first tranche of a private equity offering with one institutional investor providing for the issuance of (i) 7,000 shares of Series E convertible preferred stock at a price of $1,000 per share, and (ii) warrants to purchase 10 million shares of common stock, par value $0.0001 per share, at an initial exercise price of $0.92 per share. The Company expects to receive gross proceeds from the private equity offering of $7.0 million, in an initial tranche of $4.0 million and a second tranche, subject to shareholder approval, of $3.0 million. The first tranche of the private equity offering, including the issuance of 4,000 shares of Series E Preferred Stock and 4 million warrants, closed on January 5, 2017. The Company expects to close the second tranche of the private equity offering, including the issuance of 3,000 shares of Series E Preferred Stock and 3 million warrants, late in the first quarter of 2017.

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2016

Schedule of Valuation and Qualifying Accounts Disclosure

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, 2016
Allowance for Doubtful Accounts	$	25,000		1,901		—		(1,901	)	$	25,000
Deferred Tax Asset Valuation Allowance		43,660,035		5,867,273		—		(253,154	)⁽¹⁾		49,274,154
December 31, 2015
Allowance for Doubtful Accounts	$	38,000		—		—		(13,000	)	$	25,000
Deferred Tax Asset Valuation Allowance		38,565,925		5,342,672		—		(248,562	)⁽¹⁾		43,660,035
December 31, 2014
Allowance for Doubtful Accounts	$	35,000	$	26,042		—	$	(23,042	)	$	38,000
Deferred Tax Asset Valuation Allowance		36,108,231		3,280,605		—		(822,911	)⁽¹⁾		38,565,925

(1)

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

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

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,
	2016		2015		2014
Options		421,798		208,135		125,207
Warrants		22,790,327		3,222,071		609,084
Unvested restricted stock		—		80		1,122
Convertible preferred stock		8,603,028		2,264,086		228,143
Total		31,815,153		5,694,372		963,556

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

	Years Ended December 31,
	2016			2015			2014
Net loss	$	(14,913,151	)	$	(9,187,348	)	$	(7,766,222	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		—			(4,140,446	)		(2,955,668	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(19,846,377	)		(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	$	(34,759,528	)	$	(21,070,255	)	$	(10,721,890	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.28	)	$	(7.75	)	$	(6.15	)
Weighted average number of common shares outstanding, basic and diluted		4,777,037			2,719,285			1,743,494

Advertising and Promotional Costs

Advertising and promotional costs are expensed as incurred. Advertising and promotion expense was approximately $6,311,000, $2,499,000, and $481,000, in 2016, 2015, and 2014, respectively.

Accumulated Other Comprehensive Items

For 2016, 2015, and 2014, 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, 2016

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,
	2016		2015		2014
Options		421,798		208,135		125,207
Warrants		22,790,327		3,222,071		609,084
Unvested restricted stock		—		80		1,122
Convertible preferred stock		8,603,028		2,264,086		228,143
Total		31,815,153		5,694,372		963,556

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,
	2016			2015			2014
Net loss	$	(14,913,151	)	$	(9,187,348	)	$	(7,766,222	)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features		—			(4,140,446	)		(2,955,668	)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications		(19,846,377	)		(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	$	(34,759,528	)	$	(21,070,255	)	$	(10,721,890	)
Net loss per common share applicable to common stockholders, basic and diluted	$	(7.28	)	$	(7.75	)	$	(6.15	)
Weighted average number of common shares outstanding, basic and diluted		4,777,037			2,719,285			1,743,494

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Share-based Compensation [Abstract]

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

	Years Ended December 31,
	2016			2015			2014
Risk-free interest rate		0.9 – 1.8%			1.3 – 1.7%			1.4 – 1.8%
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, 2016 is presented below:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2015		214,813		$	18.81
Granted		575,500			1.48
Exercised		—			—
Forfeited		(7,688	)		5.67
Expired		(261	)		4,857.94
Outstanding at December 31, 2016		782,364			4.57		9.0	$	0
Vested or expected to vest at December 31, 2016		679,013			5.02		8.9		0
Exercisable at December 31, 2016		168,229			14.72		7.1		0

Inventories (Tables)

12 Months Ended

Dec. 31, 2016

Inventory Disclosure [Abstract]

Inventories

Inventories consist of the following:

	December 31,
	2016		2015
Purchased components	$	466,906	$	432,437
Work in progress		154,971		—
Finished goods		630,361		656,647
	$	1,252,238	$	1,089,084

Fixed Assets (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Fixed Assets

Fixed assets consist of the following:


	Estimated Useful Life (Years)			December 31,
	Estimated Useful Life (Years)			2016			2015
Computer and laboratory equipment		3		$	1,724,819		$	1,698,390
Furniture and equipment		3			319,046			319,046
Production equipment		7			938,357			864,287
Leasehold improvements			*		117,994			117,994
					3,100,216			2,999,717
Less – accumulated depreciation					(2,567,510	)		(2,316,183	)
				$	532,706		$	683,534

Lesser of life of lease or estimated useful life.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Components of Income Tax Expense (Benefit)

The Company’s effective income tax rate differs from the statutory federal income tax rate as follows for the years ended December 31, 2016, 2015, and 2014.

	Years Ended December 31,
	2016			2015			2014
Federal tax provision (benefit) rate		(34.0	)%		(34.0	)%		(34.0	)%
State tax provision, net of federal provision		(4.2	)		(8.5	)		(7.0	)
Permanent items		(0.2	)		(14.5	)		(3.6	)
Federal research and development credits		(0.9	)		(1.3	)		(1.0	)
Expiration of tax attribute		—			—			10.9
Valuation allowance		39.3			58.3			34.7
Effective income tax rate		—	%		—	%		—	%

Deferred Tax Assets and Liabilities

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

	December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	45,759,780		$	40,397,318
Research and development credit carryforwards		2,180,700			2,005,741
Accrued expenses		752,866			704,957
Stock-based compensation		566,487			538,321
Other		14,321			13,698
Total gross deferred tax assets		49,274,154			43,660,035
Valuation allowance		(49,274,154	)		(43,660,035	)
Net deferred tax assets	$	—		$	—

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

	December 31, 2016		Fair Value Measurements at December 31, 2016 Using
	December 31, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	833,831	$	833,831	$	—	$	—
Total	$	833,831	$	833,831	$	—	$	—
Liabilities:
Common stock warrants	$	4,641	$	—	$	—	$	4,641
Total	$	4,641	$	—	$	—	$	4,641

	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

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 $4,641 at December 31, 2016.

	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2016
	Stock Price		Exercise Price		Expected Volatility			Risk-Free Interest			Expected Term		Dividends
Warrants:
2014 Offering	$	0.74	$	8.16		64.19	%		1.33	%		2yr 6mo		none
2013 Offering	$	0.74	$	8.00		71.61	%		0.99	%		1yr 5mo		none

	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

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, 2014 and December 31, 2016.

	2014 Offering			2013 Offering			Total
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
Change in fair value of warrant liability		(223,880	)		(51,782	)		(275,662	)
Balance at December 31, 2016	$	4,112		$	529		$	4,641

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2016

Stockholders' Equity Note [Abstract]

Preferred stock and convertible preferred stock

Preferred stock and convertible preferred stock consist of the following:

	December 31,
	2016		2015
Preferred stock, $0.001 par value; 5,000,000 shares authorized at December 31, 2016 and 2015; no shares issued and outstanding at December 31, 2016 and 2015	$	—	$	—
Series B convertible preferred stock, $0.001 par value, 147,000 shares designated at December 31, 2016 and 2015, and 500 and 7,146 shares issued and outstanding at December 31, 2016 and 2015, respectively		1		7
Series C convertible preferred stock, $0.001 par value, 13,800 shares designated at December 31, 2016 and 2015, and zero and 13,800 shares issued and outstanding at December 31, 2016 and 2015, respectively		—		14
Series D convertible preferred stock, $0.001 par value, 21,300 and zero shares designated at December 31, 2016 and 2015, respectively, and 17,202.65 and zero shares issued and outstanding at December 31, 2016 and 2015, respectively		17		—

Reserved Authorized Shares of Common Stock for Future Issuance

At December 31, 2016, the Company has reserved authorized shares of common stock for future issuance as follows:

Warrants			28,206,975
Outstanding stock options			782,364
Possible future issuance under inducement plan			50,000
Possible future issuance under stock option plans			26,420
Possible future issuance under employee stock purchase plan			88,957
Total			29,154,716

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Subparagraph (SX 210.5-02(27))
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+ Details

Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Jan. 05, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization And Basis Of Presentation [Line Items]
Proceeds from issuance or sale of equity, total			$ 6,700,000
Retained Earnings (Accumulated Deficit), Total			(178,478,801)	$ (163,565,650)
Cash and Cash Equivalents, at Carrying Value, Total			3,949,135	12,462,872	$ 9,221,985	$ 9,195,753
Temporary Equity, Accretion to Redemption Value			7,500,000
Proceeds from Issuance or Sale of Equity, Total			$ 6,667,038	$ 20,141,703	$ 7,932,033
Minimum Bid Price Per Share			$ 1.00
Subsequent Event [Member]
Organization And Basis Of Presentation [Line Items]
Proceeds from Issuance or Sale of Equity, Total	$ 7,000,000
Tranche One [Member] \| Subsequent Event [Member]
Organization And Basis Of Presentation [Line Items]
Proceeds from Issuance or Sale of Equity, Total	$ 4,000,000
Tranche Two [Member] \| Subsequent Event [Member]
Organization And Basis Of Presentation [Line Items]
Proceeds from Issuance or Sale of Equity, Total		$ 3,000,000

Anti-dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Income Per Common Share (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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	31,815,153	5,694,372	963,556
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	421,798	208,135	125,207
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	22,790,327	3,222,071	609,084
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	0	80	1,122
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	8,603,028	2,264,086	228,143

Determination of Net Loss Per Common Share (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Determination of net loss per common share [Line Items]
Net loss	$ (14,913,151)	$ (9,187,348)	$ (7,766,222)
Deemed dividend attributable to preferred stockholders in connection with beneficial conversion features	0	(4,140,446)	(2,955,668)
Deemed dividend attributable to preferred stockholders in connection with preferred stock modifications	(19,846,377)	(8,332,212)	0
Return of capital to common shareholders attributable to the repurchase of preferred shares and related embedded beneficial conversion feature	0	589,751	0
Net loss applicable to common stockholders	$ (34,759,528)	$ (21,070,255)	$ (10,721,890)
Net loss per common share applicable to common stockholders, basic and diluted	$ (7.28)	$ (7.75)	$ (6.15)
Weighted average number of common shares outstanding, basic and diluted	4,777,037	2,719,285	1,743,494

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Sales Revenue Goods Net Percentage From Foreign Country	12.00%	19.00%	19.00%
Standard Product Warranty Accrual, Total	$ 45,879	$ 10,484
Marketing and Advertising Expense, Total	6,311,000	2,499,000	$ 481,000
Deferred Revenue and Credits, Current	1,247,545	489,467
Other Deferred Credits, Current	619,309	262,295
Deferred Revenue Current	628,236	227,172
Deferred Costs, Current	910,595	378,440
Accrued Sales Return Allowance Current	$ 488,200	$ 65,111
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%
Two Customers [Member] \| Accounts Receivable [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration Risk, Percentage	41.00%

Weighted Average Grant-Date Fair Value Used in the Calculation of Stock-Based Compensation Expense (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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	1.80%	1.70%	1.80%
Minimum [Member]
Risk-free interest rate	0.90%	1.30%	1.40%

Summary of option activity (Detail)	12 Months Ended
Summary of option activity (Detail)	Dec. 31, 2016 USD ($) $ / shares shares
Summary Of Option Activity [Line Items]
Number of Outstanding at December 31, 2015 \| shares	214,813
Number of Options Granted \| shares	575,500
Number of Options Exercised \| shares	0
Number of Options Forfeited \| shares	(7,688)
Number of Options Expired \| shares	(261)
Number of Options Outstanding at December 31, 2016 \| shares	782,364
Number of Options, Vested or expected to vest at December 31, 2016 \| shares	679,013
Number of Options, Exercisable at December 31, 2016 \| shares	168,229
Weighted Average Exercise Price Outstanding at December 31, 2015 \| $ / shares	$ 18.81
Weighted Average Exercise Price Granted \| $ / shares	1.48
Weighted Average Exercise Price Exercised \| $ / shares	0
Weighted Average Exercise Price Forfeited \| $ / shares	5.67
Weighted Average Exercise Price, Expired \| $ / shares	4,857.94
Weighted Average Exercise Price Outstanding at December 31, 2016 \| $ / shares	4.57
Weighted Average Exercise Price, Vested or expected to vest at December 31, 2016 \| $ / shares	5.02
Weighted Average Exercise Price, Exercisable at December 31, 2016 \| $ / shares	$ 14.72
Weighted Average Remaining Contractual Life (in years), Outstanding at December 31, 2016	9 years
Weighted Average Remaining Contractual Life (in years), Vested or expected to vest at December 31, 2016	8 years 10 months 24 days
Weighted Average Remaining Contractual Life (in years), Exercisable at December 31, 2016	7 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding at December 31, 2016 \| $	$ 0
Aggregate Intrinsic Value, Vested or expected to vest at December 31, 2016 \| $	0
Aggregate Intrinsic Value, Exercisable at December 31, 2016 \| $	$ 0

Stock-Based Compensation - Additional Information (Detail) - USD ($)		1 Months Ended		12 Months Ended
	May 03, 2016	May 31, 2010	Jun. 30, 2004	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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	500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				782,364	214,813
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance				$ 4.57	$ 18.81
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value				0.85	2.95	$ 4.24
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				$ 487,922
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares, Beginning Balance				782,364
Share Based Compensation Arrangement By Share Based Payment Award Options Nonvested Weighted Average Price Per Shares				$ 4.57
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				3 years 2 months 12 days
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options, Total				$ 29,000	$ 38,000	$ 24,000
Allocated Share-based Compensation Expense				$ 225,408	$ 302,415	$ 289,873
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				1,031,570
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period				272,786
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				732,364
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance				$ 4.37
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				26,420
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
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				50,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance				$ 7.52
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				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				35,002	15,443
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				88,957
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 3, 2016, the stockholders of the Company approved the Companys Third 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 100,000 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%

Inventories (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Line Items]
Purchased components	$ 466,906	$ 432,437
Work in progress	154,971	0
Finished goods	630,361	656,647
Inventories	$ 1,252,238	$ 1,089,084

Fixed Assets (Details) - USD ($)

12 Months Ended

Dec. 31, 2016

Dec. 31, 2015

Less - accumulated depreciation

$ 3,100,216

$ 2,999,717

(2,567,510)

(2,316,183)

Fixed assets, net

532,706

683,534

Computer And Laboratory Equipment [Member]

$ 1,724,819

1,698,390

Furniture And Equipment [Member]

3 years

$ 319,046

319,046

Production Equipment [Member]

3 years

$ 938,357

864,287

Leasehold Improvements [Member]

7 years

$ 117,994