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Summary of Significant Accounting Policies - Additional Information 2 (Detail)
$ / shares in Units, $ in Thousands
 3 Months Ended
Mar. 31, 2018
USD ($)
Unit
Product
$ / shares
$ / EquityUnit
shares
Mar. 31, 2017
USD ($)
Dec. 31, 2017
shares
Operations And Summary Of Significant Accounting Policies [Line Items]      
Stock-based compensation expense recognized $ 1,601 $ 1,265  
Number of primary products | Product 2    
Contract cash settlement max days 25 days    
Contract cancellable notice term 30 days    
Accounts Receivable related to satisfied performance obligations and unconditional right to consideration $ 26,100    
Restricted Stock      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Number of shares granted | shares 445,801    
Restricted stock grant date fair value $ 3,800    
Grant date fair value of share units, per share | $ / shares $ 8.46    
Shares of unvested restricted stock outstanding | shares 911,319   619,867
Weighted average grant date fair value of stock grants per share | $ / shares $ 8.41    
Unrecognized compensation cost related to unvested restricted stock $ 6,500    
Period in which compensation cost expected to be recognized 2 years 4 months 24 days    
Potential Performance Shares (PSU)      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Period in which compensation cost expected to be recognized 2 years 6 months    
Number of units granted | Unit 360,801    
Performance share units grant date fair value $ 4,500    
Grant date fair value of share units, per unit | $ / EquityUnit 12.52    
Number of performance stock units ("PSUs") outstanding | Unit 514,336    
Weighted average grant date fair value of PSUs per unit | $ / EquityUnit 13.83    
Minimum final number of shares of common stock issuable based on performance multiplier | shares 0    
Maximum final number of shares of common stock issuable based on performance multiplier | shares 1,028,672    
Unrecognized expense, performance share units $ 6,800    
General and Administrative Expense      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Stock-based compensation expense recognized $ 1,600 $ 1,300