Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	$ 27,086
Current [Member]
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	20,232
Deferred Revenue [Member]
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	17,261
Deferred Revenue [Member] | Current [Member]
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	15,889
Unbilled Backlog [Member]
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	9,825
Unbilled Backlog [Member] | Current [Member]
Disaggregation of Revenue [Line Items]
Deferred revenue expected to be recognized in future	4,343
Accounting Standards Update 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Revenue related to the estimation of per-unit royalties	4,300
Deferred revenue expected to be recognized in future		$ 6,800
Revenue recognition performance obligation settled	4,300
Capitalized incremental costs to obtain contracts	1,400
Accounting Standards Update 2014-09 [Member] | Prepaid Expenses and Other Current Assets [Member]
Disaggregation of Revenue [Line Items]
Capitalized short-term incremental costs to obtain contracts	500
Accounting Standards Update 2014-09 [Member] | Other Assets [Member]
Disaggregation of Revenue [Line Items]
Capitalized long-term incremental costs to obtain contracts	$ 900
Accounting Standards Update 2014-09 [Member] | Minimum [Member]
Disaggregation of Revenue [Line Items]
Estimated amortization period	3 years
Accounting Standards Update 2014-09 [Member] | Maximum [Member]
Disaggregation of Revenue [Line Items]
Estimated amortization period	10 years