Information about Operating Segments and Geographic Areas - Profit and Loss Information of Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenue	$ 19,469	$ 19,653	$ 18,848	$ 22,841	$ 26,797	$ 22,467	$ 22,738	$ 25,439	$ 80,811	$ 97,441
Cost of revenue									62,689	81,621
Gross profit	3,616	4,380	3,873	6,253	3,954	3,677	3,893	4,296	18,122	15,820
Operating expenses									27,543	16,978
Other income, net									214	247
Income tax benefit (expense)									149	(141)
Net loss	$ (4,232)	$ (2,468)	$ (2,560)	$ 202	$ (1,261)	$ (106)	$ (185)	$ 500	(9,058)	(1,052)
Third Party Software [Member]
Segment Reporting Information [Line Items]
Revenue									65,755	80,231
Cost of revenue									55,161	67,853
Gross profit									10,594	12,378
Proprietary Software [Member]
Segment Reporting Information [Line Items]
Revenue									4,646	1,939
Cost of revenue									163	329
Gross profit									4,483	1,610
Professional Engineering Services [Member]
Segment Reporting Information [Line Items]
Revenue									10,410	15,271
Cost of revenue									7,365	13,439
Gross profit									$ 3,045	$ 1,832