Shareholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

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 September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Dividend yield		0	%		0	%		0	%		0	%
Expected life	4.4 years			3.3 years			5.3 years			3.3 years
Expected volatility		56	%		52	%		55	%		52	%
Risk-free interest rate		2.7	%		1.7	%		2.5	%		1.7	%

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 September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cost of revenue — professional engineering service	$	11	$	13	$	30	$	98
Selling, general and administrative		237		457		421		1,061
Research and development		57		70		169		191
Total stock-based compensation expense	$	305	$	540	$	620	$	1,350
Per diluted share	$	0.02	$	0.04	$	0.05	$	0.11

Summary of Stock Option Activity

The following table summarizes stock option activity under the Plans:

						Weighted Average
						Remaining
				Weighted Average		Contractual Life		Aggregate
	Number of Shares			Exercise Price		(in years)		Intrinsic Value
Balance at December 31, 2017		1,912,161		$	4.88		7.61	$	781,735
Granted		283,893			3.78
Exercised		(2,422	)		3.59
Forfeited		(385,736	)		4.94
Expired		(332,036	)		4.17
Balance at September 30, 2018		1,475,860		$	4.81		6.88	$	3,950
Vested and expected to vest at September 30, 2018		1,366,764		$	4.82		6.73	$	3,259
Exercisable at September 30, 2018		954,862		$	4.84		5.97	$	—

Summary of Certain Additional Information about Stock Options

The following table summarizes certain information about stock options:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Weighted average grant-date fair value of options granted during the period	$	1.02	$	2.45	$	1.89	$	2.62
Options in-the-money (in shares)		26,000		1,261,705		26,000		1,261,705
Aggregate intrinsic value of options exercised during the period	$	-	$	31,338	$	1,853	$	89,171

Summary of Restricted Stock Unit Activity

The following table summarizes RSU activity under the Plans:

	Number of			Weighted Average
	Shares			Award Price
Unvested at December 31, 2017		116,968		$	5.33
Granted		159,760			3.06
Vested		(82,868	)		4.55
Forfeited		(52,441	)		4.53
Unvested at September 30, 2018		141,419		$	3.51
Expected to vest after September 30, 2018		125,050		$	3.46

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 September 30, 2018:

	September 30, 2018
Stock options outstanding		1,475,860
Restricted stock units outstanding		141,419
Stock options and restricted stock units available for future grant		1,515,816
Common stock reserved for future issuance		3,133,095