Quarterly report pursuant to Section 13 or 15(d)

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

v3.2.0.727
Marketable Securities and Fair Value - Summary of Company's Available-for-Sale Securities (Detail) - USD ($)
$ in Thousands
Jun. 30, 2015
Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis $ 56,468 $ 50,222
Unrealized Gain 4 4
Unrealized Loss (22) (17)
Fair Value 56,450 50,209
Money Market Funds    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 6,024 3,369
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 6,024 3,369
Certificates of Deposit    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 356 2,505
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 356 2,505
Corporate Debt Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 27,853 28,094
Unrealized Gain 1 1
Unrealized Loss (21) (14)
Fair Value 27,833 28,081
U.S. Government Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 21,708 19,123
Unrealized Gain 2 3
Unrealized Loss (1) (3)
Fair Value 21,709 19,123
Municipal Securities    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 1,955  
Unrealized Gain 1  
Unrealized Loss 0  
Fair Value 1,956  
Commercial Paper    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 8,880 5,499
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 8,880 5,499
Marketable Securities Including Cash Equivalents    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 66,776 58,590
Unrealized Gain 4 4
Unrealized Loss (22) (17)
Fair Value 66,758 58,577
Less Cash Equivalents    
Schedule Of Available For Sale Securities [Line Items]    
Cost Basis 10,308 8,368
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value $ 10,308 $ 8,368