Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2018

Stockholders' Equity Note [Abstract]

Summary of stock-based compensation expense

The following table summarizes stock-based compensation expense and the impact it had on operations for the periods presented (in thousands):

	Three months ended March 31,
	2018		2017
Cost of sales	$	9	$	18
Product development	25		13
Selling, general, and administrative	161		176
Total stock-based compensation	$	195	$	207

Schedule of valuation assumptions

Estimates utilized in the calculation include the expected life of the option, risk-free interest rate, and expected volatility, and are further comparatively detailed as follows:

	Three months ended March 31,
	2018			2017
Fair value of options issued	$	1.74		$	2.79
Exercise price	$	2.46		$	3.71
Expected life of options (in years)	5.8			5.8
Risk-free interest rate	2.3		%	2.1		%
Expected volatility	84.3		%	92.2		%
Dividend yield	0.0		%	0.0		%

Summary of option activity

A summary of option activity under all plans for the three months ended March 31, 2018 is presented as follows:

	Number of Options		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in years)
Balance at December 31, 2017	248,512		$	5.76
Granted	25,035		2.46
Exercised	—		—
Canceled/forfeited	(20,523	)	10.09
Expired	—		—
Balance at March 31, 2018	253,024		$	5.08	7.8
Vested and expected to vest at March 31, 2018	232,906		$	5.26	7.6
Exercisable at March 31, 2018	126,505		$	6.95	6.5

Restricted stock units

A summary of restricted stock unit activity under all plans for the three months ended March 31, 2018 is presented as follows:

	Restricted Stock Units		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life (in years)
Balance at December 31, 2017	306,142		$	3.37
Granted	421,514		2.48
Released	(74,655	)	4.10
Canceled/forfeited	(11,571	)	3.80
Balance at March 31, 2018	641,430		$	2.69	2.7