Revenue Recognition - Summary of Impact of Adoption of Accounting Standards (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Revenue:
Software	$ 19,451	$ 20,167
Professional engineering service	3,390	5,272
Total revenue	22,841	25,439
Cost of revenue:
Software	14,114	17,161
Professional engineering service	2,474	3,982
Total cost of revenue	16,588	21,143
Gross profit	6,253	4,296
Operating expenses:
Selling, general and administrative	4,865	3,206
Research and development	1,347	441
Total operating expenses	6,212	3,647
Income from operations	41	649
Net income (loss)	$ 202	$ 500
Basic income(loss) per share	$ 0.02	$ 0.04
Diluted income (loss) per share	$ 0.02	$ 0.04
Assets:
Contract Assets	$ 883
Liabilities:
Deferred revenue - current	1,908		$ 2,064
Deferred revenue - noncurrent	115		1,798
Shareholders' Equity:
Accumulated deficit	(96,016)		$ (96,607)
Topic 606 [Member] | Balances without adoption of Topic 606 [Member]
Revenue:
Software	17,138
Professional engineering service	2,944
Total revenue	20,082
Cost of revenue:
Software	14,114
Professional engineering service	2,150
Total cost of revenue	16,264
Gross profit	3,818
Operating expenses:
Selling, general and administrative	4,724
Research and development	1,347
Total operating expenses	6,071
Income from operations	(2,253)
Net income (loss)	$ (2,092)
Basic income(loss) per share	$ (0.17)
Diluted income (loss) per share	$ (0.17)
Assets:
Contract Assets	$ 904
Liabilities:
Deferred revenue - current	3,047
Deferred revenue - noncurrent	1,332
Shareholders' Equity:
Accumulated deficit	(98,352)
Topic 606 [Member] | Impact of changes in accounting policies, Effect of Change Higher/(Lower) [Member]
Revenue:
Software	2,313
Professional engineering service	446
Total revenue	2,759
Cost of revenue:
Professional engineering service	324
Total cost of revenue	324
Gross profit	2,435
Operating expenses:
Selling, general and administrative	141
Total operating expenses	141
Income from operations	2,294
Net income (loss)	$ 2,294
Basic income(loss) per share	$ 0.19
Diluted income (loss) per share	$ 0.19
Assets:
Contract Assets	$ (21)
Liabilities:
Deferred revenue - current	(1,139)
Deferred revenue - noncurrent	(1,217)
Shareholders' Equity:
Accumulated deficit	$ 2,336