Revenue Recognition - Disaggregated Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 16,694	$ 19,653	$ 56,575	$ 61,342
Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	14,241	16,240	47,297	48,542
Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	796	1,200	2,872	4,335
Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	1,657	2,213	6,406	8,465
North America [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	15,441	17,982	52,909	57,480
North America [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	13,715	15,615	45,115	46,867
North America [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	288	532	2,236	3,650
North America [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	1,438	1,835	5,558	6,963
Europe [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	674	796	2,502	2,433
Europe [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	526	520	1,821	1,380
Europe [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2		107
Europe [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	146	276	574	1,053
Asia [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	579	875	1,164	1,429
Asia [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue		105	361	295
Asia [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	506	668	529	685
Asia [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 73	$ 102	$ 274	$ 449