v3.8.0.1
Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Advertising Expense                 $ 21,900,000 $ 11,900,000 $ 4,000,000
Accumulated deficit $ 671,800,000       $ 621,000,000       671,800,000 621,000,000  
Cash, cash equivalents and short-term investments 548,600,000               548,600,000    
Working capital 605,800,000               $ 605,800,000    
Maturity Threshold Of Investments Classified To Cash Equivalents                 90    
Letters of Credit Outstanding, Amount 4,400,000       4,300,000       $ 4,400,000 4,300,000  
Sales return period                 30 days    
Revenues 221,000,000 $ 184,600,000 $ 170,600,000 $ 142,300,000 $ 171,200,000 $ 148,600,000 $ 137,300,000 $ 116,200,000      
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 0               $ 0    
TCJA, Provisional tax expense (benefit) offset by valuation allowance                 105,700,000    
TCJA, Provisional income tax expense (benefit)                 0    
Foreign Earnings Repatriated                 0    
Cumulative Foreign Deficits                 $ 41,200,000    
Share-based compensation, excess tax benefits       $ 161,800,000              
Computer equipment                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Property, Plant and Equipment, Useful Life                 3 years    
Furniture and fixtures                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Property, Plant and Equipment, Useful Life                 5 years    
Customer [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Concentration Risk, Percentage                 10.00%    
Byram [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Revenues                 $ 98,500,000 $ 96,500,000 $ 74,100,000
Concentration Risk, Percentage                 14.00% 17.00% 18.00%
Edgepark [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Revenues                 $ 120,400,000 $ 93,200,000 $ 66,100,000
Concentration Risk, Percentage                 17.00% 16.00% 16.00%
Accounting Standards Update 2016-09 [Member] | Accumulated deficit [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Adoption of ASU 2016-09 $ (600,000)               $ (600,000)    
Minimum [Member] | Machinery and Equipment [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Property, Plant and Equipment, Useful Life                 2 years    
Maximum [Member] | Machinery and Equipment [Member]                      
Organization And Summary Of Significant Accounting Policies [Line Items]                      
Property, Plant and Equipment, Useful Life                 15 years