Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 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 June 30,				Six months ended June 30,
	2018		2017		2018		2017
Cost of sales	$	10	$	12	$	19	$	30
Product development	30		16		55		29
Selling, general, and administrative	195		198		356		374
Total stock-based compensation	$	235	$	226	$	430	$	433

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:

	Six months ended June 30,
	2018			2017
Fair value of options issued	$	1.74		$	2.72
Exercise price	$	2.46		$	3.63
Expected life of options (in years)	5.8			5.8
Risk-free interest rate	2.3		%	2.1		%
Expected volatility	84.3		%	91.9		%
Dividend yield	0.0		%	0.0		%

Summary of option activity

A summary of option activity under all plans for the six months ended June 30, 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	(21,428	)	9.94
Expired	(10,000	)	20.00
Balance at June 30, 2018	242,119		$	4.46	7.8
Vested and expected to vest at June 30, 2018	226,357		$	4.56	7.8
Exercisable at June 30, 2018	139,578		$	5.45	7.1

Restricted stock units

A summary of restricted stock unit activity under all plans for the six months ended June 30, 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	503,183		2.44
Released	(180,293	)	3.18
Canceled/forfeited	(24,120	)	3.51
Balance at June 30, 2018	604,912		$	2.65	2.7