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