Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements and Marketable Securities - Summary of Company's Available-for-Sale Securities (Detail)

v3.3.1.900
Fair Value Measurements and Marketable Securities - Summary of Company's Available-for-Sale Securities (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis $ 39,112 $ 50,222
Unrealized Gain 1 4
Unrealized Loss (22) (17)
Fair Value 39,091 50,209
Money Market Funds    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 5,421 3,369
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 5,421 3,369
Certificates of Deposit    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 696 2,505
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 696 2,505
Corporate Debt Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 12,578 28,094
Unrealized Gain 1 1
Unrealized Loss (8) (14)
Fair Value 12,571 28,081
Government Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 21,783 19,123
Unrealized Gain 0 3
Unrealized Loss (14) (3)
Fair Value 21,769 19,123
Municipal Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 1,908  
Unrealized Gain 0  
Unrealized Loss 0  
Fair Value 1,908  
Commercial Paper    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 6,145 5,499
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 6,145 5,499
Marketable Securities Including Cash Equivalents    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 48,531 58,590
Unrealized Gain 1 4
Unrealized Loss (22) (17)
Fair Value 48,510 58,577
Less Cash Equivalents    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis (9,419) (8,368)
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value $ (9,419) $ (8,368)