Shareholders' Equity (Tables)

3 Months Ended

Mar. 31, 2019

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 March 31,
	2019			2018
Dividend yield		0	%		0	%
Expected life	6.0 years			5.4 years
Expected volatility		64	%		54	%
Risk-free interest rate		2.2	%		2.4	%

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 March 31,
	2019			2018
Cost of revenue — professional engineering service	$	6		$	11
Selling, general and administrative		188			264
Research and development		(26	)		56
Total stock-based compensation expense	$	168		$	331
Per diluted share	$	0.01		$	0.03

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, 2018		1,390,012		$	4.77		6.83	$	—
Granted		575,625			1.97
Exercised		—			—
Forfeited		(54,194	)		4.90
Expired		(20,296	)		5.17
Balance at March 31, 2019		1,891,147		$	3.90		6.96	$	180
Vested and expected to vest at March 31, 2019		1,638,226		$	4.13		6.55	$	117
Exercisable at March 31, 2019		979,630		$	4.85		4.00	$	—

Summary of Certain Additional Information about Stock Options

The following table summarizes certain information about stock options:

	Three Months Ended March 31,
	2019		2018
Weighted average grant-date fair value of options granted during the period	$	1.97	$	2.09
Options in-the-money (in shares)		6,000		737,632
Aggregate intrinsic value of options exercised during the period	$	—	$	275

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, 2018		186,516		$	2.88
Granted		—			—
Vested		(45,725	)		2.82
Forfeited		(18,876	)		4.23
Unvested at March 31, 2019		121,915		$	2.69
Expected to vest after March 31, 2019		114,770		$	2.65

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 March 31, 2019:

	March 31, 2019
Stock options outstanding		1,891,147
Restricted stock units outstanding		121,915
Stock options and restricted stock units available for future grant		1,593,641
Common stock reserved for future issuance		3,606,703