Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2017

Equity [Abstract]

Summary of Stock Based Compensation Expense

Stock compensation expense (in thousands) was allocated between departments as follows:

	Three Months Ended March 31,
	2017		2016
Research & Development	$	36	$	33
Sales & Marketing	6		(31		)
General & Administrative	143		134
Total	$	185	$	136

Schedule of Fair Value of Award Granted Using Black-Scholes Option Pricing Model

The fair value of each award granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions for the three months ended March 31, 2017:

	Three months ended
	March 31, 2017
Expected life (years)	10
Risk-free interest rate	1.3% - 1.7%
Volatility	65% - 73%
Dividend rate	—%

Summary of Stock Option Transactions

The following table summarizes stock option transactions for the three months ended March 31, 2017 as issued under the Plans:

	Shares Available for Grant		Number of Options Outstanding		Weighted-Average Exercise Price per Share		Weighted Average Remaining Contractual Term
							(in years)
Balance at December 31, 2016	958,856		2,908,430		$	3.42	8.48
Additional shares authorized	671,478		—
Amendment to plan to authorize additional shares	8,929,188		—
Options granted	(60,000	)	60,000		0.65
Options exercised	—		—
Options canceled/forfeited	33,583		(33,583	)	4.46
Balance at March 31, 2017	10,533,105		2,934,847		3.35		8.28
Options vested at March 31, 2017			1,593,754		$	3.98	7.98
Options vested and expected to vest at March 31, 2017			2,934,847		$	3.35	8.28