Annual report pursuant to Section 13 and 15(d)

Fair Value Measurement - Summary of Fair Value Measurements of Cash Equivalents, Available-for-Sale Securities and Contingent Consideration Liability (Detail)

v3.6.0.2
Fair Value Measurement - Summary of Fair Value Measurements of Cash Equivalents, Available-for-Sale Securities and Contingent Consideration Liability (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents $ 18,992 $ 65,937
Total marketable securities 120,474 139,518
Total cash equivalents and marketable securities 139,466 205,455
Money market funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents 18,992 25,070
Commercial paper securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents   2,000
Total marketable securities 23,185 30,717
Level 1 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents 18,992 65,937
Total cash equivalents and marketable securities 18,992 65,937
Level 1 [Member] | Money market funds [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents 18,992 25,070
Level 1 [Member] | Commercial paper securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents   2,000
Level 2 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total marketable securities 120,474 139,518
Total cash equivalents and marketable securities 120,474 139,518
Level 2 [Member] | Commercial paper securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total marketable securities 23,185 30,717
Corporate debt securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total marketable securities 10,004 17,263
Corporate debt securities [Member] | Level 2 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total marketable securities 10,004 17,263
U.S. government sponsored entity debt securities [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents   38,867
Total marketable securities 87,285 91,538
U.S. government sponsored entity debt securities [Member] | Level 1 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents   38,867
U.S. government sponsored entity debt securities [Member] | Level 2 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total marketable securities $ 87,285 $ 91,538