Revenue Recognition - Disaggregated Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 15,096	$ 20,678
Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	13,101	16,064
Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	251	1,795
Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	1,744	2,819
North America [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	14,528	19,289
North America [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	12,727	15,119
North America [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	244	1,683
North America [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	1,557	2,487
Europe [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	461	939
Europe [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	320	593
Europe [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	6	100
Europe [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	135	246
Asia [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	107	450
Asia [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	54	352
Asia [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	1	12
Asia [Member] | Professional Engineering Service [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 52	$ 86