Revenue Recognition - Summary of Impact of Adoption of Accounting Standards (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Revenue:
Software	$ 15,986		$ 18,735	$ 35,437	$ 38,902
Professional engineering service	2,862		4,003	6,252	9,275
Total revenue	18,848		22,738	41,689	48,177
Cost of revenue:
Software	13,142		15,459	27,256	32,620
Professional engineering service	1,833		3,386	4,307	7,368
Total cost of revenue	14,975		18,845	31,563	39,988
Gross profit	3,873		3,893	10,126	8,189
Operating expenses:
Selling, general and administrative	5,046		3,204	9,911	6,410
Research and development	1,446		774	2,793	1,215
Total operating expenses	6,492		3,978	12,704	7,625
Income (loss) from operations	(2,619)		(85)	(2,578)	564
Net income (loss)	$ (2,560)		$ (185)	$ (2,358)	$ 315
Basic and diluted loss per share	$ (0.20)			$ (0.19)
Assets:
Contract Assets	$ 636			$ 636
Liabilities:
Deferred revenue - current	2,287			2,287		$ 2,064
Deferred revenue - noncurrent	162			162		1,798
Shareholders' Equity:
Accumulated deficit	(98,576)			(98,576)		$ (96,607)
Topic 606 [Member] | Balances without adoption of Topic 606 [Member]
Revenue:
Software	16,257			33,353
Professional engineering service	2,985			5,929
Total revenue	19,242			39,282
Cost of revenue:
Software	13,142			27,256
Professional engineering service	1,956			4,106
Total cost of revenue	15,098			31,362
Gross profit	4,144			7,920
Operating expenses:
Selling, general and administrative	5,040			9,764
Research and development	1,446			2,793
Total operating expenses	6,486			12,557
Income (loss) from operations	(2,342)			(4,637)
Net income (loss)	$ (2,283)			$ (4,417)
Basic and diluted loss per share	$ (0.18)			$ (0.35)
Assets:
Contract Assets	$ 540			$ 540
Liabilities:
Deferred revenue - current	3,293			3,293
Deferred revenue - noncurrent	1,120			1,120
Shareholders' Equity:
Accumulated deficit	(100,635)			(100,635)
Topic 606 [Member] | Effect of Change Higher/(Lower) [Member]
Revenue:
Software	(271)			2,084
Professional engineering service	(123)			323
Total revenue	(394)	$ 2,800		2,407
Cost of revenue:
Professional engineering service	(123)			201
Total cost of revenue	(123)			201
Gross profit	(271)			2,206
Operating expenses:
Selling, general and administrative	6			147
Total operating expenses	6			147
Income (loss) from operations	(277)			2,059
Net income (loss)	$ (277)			$ 2,059
Basic and diluted loss per share	$ (0.02)			$ 0.16
Assets:
Contract Assets	$ 96			$ 96
Liabilities:
Deferred revenue - current	(1,006)			(1,006)
Deferred revenue - noncurrent	(958)			(958)
Shareholders' Equity:
Accumulated deficit	$ 2,059			$ 2,059