Revenue Recognition - Disaggregated Revenue (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 22,841
Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	19,451
Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	16,797
Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2,654
Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	3,390
North America [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	21,770
North America [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	18,941
North America [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	16,296
North America [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2,645
North America [Member] | Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2,829
Europe [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	822
Europe [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	424
Europe [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	424
Europe [Member] | Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	398
Asia [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	249
Asia [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	86
Asia [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	77
Asia [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	9
Asia [Member] | Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	163
Products transferred at a point in time [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	20,041
Products transferred at a point in time [Member] | Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	19,451
Products transferred at a point in time [Member] | Software [Member] | Third Party Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	16,797
Products transferred at a point in time [Member] | Software [Member] | Proprietary Software [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2,654
Products transferred at a point in time [Member] | Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	590
Products and services transferred over time [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	2,800
Products and services transferred over time [Member] | Professional Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Disaggregated revenue	$ 2,800