Shareholders' Equity (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Fair Values of Stock Option Grants Estimated with Weighted Average Assumptions

The fair values of our stock option grants were estimated with the following weighted average assumptions:

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
Dividend yield		0	%		0	%		0	%		0	%
Expected life	3.3 years			3.4 years			3.3 years			3.4 years
Expected volatility		52	%		55	%		53	%		55	%
Risk-free interest rate		1.6	%		1.1	%		1.7	%		1.1	%

Stock-Based Compensation Expense

The impact on our results of operations from stock-based compensation expense was as follows (in thousands, except per share amounts):  

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Cost of revenue — service	$	20	$	36	$	85	$	173
Selling, general and administrative		320		150		604		357
Research and development		71		29		121		98
Total stock-based compensation expense	$	411	$	215	$	810	$	628
Per diluted share	$	0.03	$	0.02	$	0.06	$	0.05

Summary of Stock Option Activity

The following table summarizes stock option activity under the Plans for the six months ended June 30, 2017:

Stock Options	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Balance at January 1, 2017		1,846,768		$	4.84		8.19	$	2,138,361
Granted		89,125			5.33
Exercised		(30,079	)		3.82
Forfeited		(48,550	)		5.24
Expired		(25,445	)		5.56
Balance at June 30, 2017		1,831,819		$	4.86		7.96	$	1,755,761
Vested and expected to vest at June 30, 2017		1,694,577		$	4.82		7.86	$	1,700,861
Exercisable at June 30, 2017		838,272		$	4.25		6.65	$	1,334,204

Summary of Certain Information about Stock Options

The following table summarizes certain information about stock options:

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Weighted-average grant-date fair value of option    grants for the period	$	2.64	$	2.87	$	2.80	$	3.05
Options in-the-money at period end		1,755,762		948,745		1,755,762		948,745
Aggregate intrinsic value of options exercised	$	17,412	$	310,756	$	57,833	$	360,086

Summary of Restricted Stock Unit Activity

The following table summarizes RSU activity for the six months ended June 30, 2017:

	Number of Shares			Weighted Average Grant Date Fair Value
Unvested at January 1, 2017		119,606		$	5.60
Granted		61,409			4.89
Vested		(30,635	)		5.76
Forfeited		—			—
Unvested at June 30, 2017		150,380		$	5.28
Expected to vest after June 30, 2017		134,077		$	5.28

Summary of Shares of Common Stock Reserved for Future Issuance under Plans

The following table summarizes our shares of common stock reserved for future issuance under the Plans as of June 30, 2017:

Stock options outstanding	1,831,819
RSUs outstanding	150,380
Stock awards available for future grant	1,312,621
Common stock reserved for future issuance	3,294,820