Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Summary of Stock Based Compensation Expense

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Research & Development	$	43	$	41	$	140	$	116
Sales & Marketing	—		11		7		22
General & Administrative	183		154		708		422
Total	$	226	$	206	$	855	$	560

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

No options were granted during the three months ended September 30, 2017 and 2016, and the fair value of each award granted for the nine months ended September 30, 2017 and 2016, was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions.

	Three Months Ended September 30,		Nine Months Ended September 30,
	2017	2016	2017	2016
Expected life (years)	-	-	5.5-6.08	5.5-6.08
Risk-free interest rate	-	-	1.9%-2.2%	1.3%-1.7%
Volatility	-	-	61%-69%	65% - 73%
Dividend rate	-	-	—%	—%

Summary of Stock Option Transactions

The following table summarizes stock option transactions for the nine months ended September 30, 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 January 1, 2017	191,771		581,686		$	17.10	8.48
Additional shares authorized	134,295		—
Amendment to plan to authorize additional shares	1,785,837		—
Options granted	(622,755	)	622,755		3.05
Options exercised	—		—
Options canceled/forfeited	132,437		(132,437	)	9.30
Balance at September 30, 2017	1,621,585		1,072,004		9.9		8.11
Options vested at September 30, 2017			533,202		$	14.05	6.96
Options vested and expected to vest at September 30, 2017			1,072,004		$	9.90	8.11