Quarterly report pursuant to Section 13 or 15(d)

Cash, Cash Equivalents and Short-Term Investments - Gross Unrealized Gains and Losses (Details)

v3.8.0.1
Cash, Cash Equivalents and Short-Term Investments - Gross Unrealized Gains and Losses (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Cash equivalents and available-for-sale securities    
Amortized Cost $ 62,599 $ 65,048
Gross Unrealized Gains   5
Gross Unrealized Losses (7) (23)
Fair Value 62,592 65,030
U.S. treasury bills    
Cash equivalents and available-for-sale securities    
Amortized Cost 3,000 4,300
Fair Value 3,000 4,300
Government-sponsored enterprises securities    
Cash equivalents and available-for-sale securities    
Amortized Cost 3,656 16,457
Gross Unrealized Gains   3
Gross Unrealized Losses (1) (1)
Fair Value 3,655 16,459
Corporate bonds and commercial paper    
Cash equivalents and available-for-sale securities    
Amortized Cost 55,943 44,291
Gross Unrealized Gains   2
Gross Unrealized Losses (6) (22)
Fair Value $ 55,937 $ 44,271