Quarterly report pursuant to Section 13 or 15(d)

Cash, Cash Equivalents and Investments - Summary of available-for-sale securities' fair value and gross unrealized losses (Details)

v3.5.0.2
Cash, Cash Equivalents and Investments - Summary of available-for-sale securities' fair value and gross unrealized losses (Details) - USD ($)
$ in Thousands
Jun. 30, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, continuous unrealized loss position, twelve months or less, fair value $ 17,796 $ 81,045
Available-for-sale securities, continuous unrealized loss position, twelve months or less, gross unrealized losses (7) (295)
Available-for-sale securities, continuous unrealized loss position, more than twelve months, fair value 9,763 8,531
Available-for-sale securities, continuous unrealized loss position, more than twelve months, gross unrealized losses (10) (54)
Available-for-sale securities, continuous unrealized loss position, fair value 27,559 89,576
Available-for-sale securities, continuous unrealized loss position, gross unrealized losses (17) (349)
Corporate debt securities    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, continuous unrealized loss position, twelve months or less, fair value 17,796 64,804
Available-for-sale securities, continuous unrealized loss position, twelve months or less, gross unrealized losses (7) (293)
Available-for-sale securities, continuous unrealized loss position, more than twelve months, fair value 9,763 8,531
Available-for-sale securities, continuous unrealized loss position, more than twelve months, gross unrealized losses (10) (54)
Available-for-sale securities, continuous unrealized loss position, fair value 27,559 73,335
Available-for-sale securities, continuous unrealized loss position, gross unrealized losses $ (17) (347)
U.S. government and government agency debt securities    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, continuous unrealized loss position, twelve months or less, fair value   16,241
Available-for-sale securities, continuous unrealized loss position, twelve months or less, gross unrealized losses   (2)
Available-for-sale securities, continuous unrealized loss position, more than twelve months, fair value   0
Available-for-sale securities, continuous unrealized loss position, more than twelve months, gross unrealized losses   0
Available-for-sale securities, continuous unrealized loss position, fair value   16,241
Available-for-sale securities, continuous unrealized loss position, gross unrealized losses   $ (2)