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)

v3.4.0.3
Cash, Cash Equivalents and Investments - Summary of available-for-sale securities' fair value and gross unrealized losses (Details) - USD ($)
$ in Thousands
Mar. 31, 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 $ 24,891 $ 81,045
Available-for-sale securities, continuous unrealized loss position, twelve months or less, gross unrealized loss (30) (295)
Available-for-sale securities, continuous unrealized loss position, more than twelve months, fair value 19,488 8,531
Available-for-sale securities, continuous unrealized loss position, more than twelve months, gross unrealized loss (42) (54)
Available-for-sale securities, continuous unrealized loss position, fair value 44,379 89,576
Available-for-sale securities, continuous unrealized loss position, gross unrealized loss (72) (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 24,891 64,804
Available-for-sale securities, continuous unrealized loss position, twelve months or less, gross unrealized loss (30) (293)
Available-for-sale securities, continuous unrealized loss position, more than twelve months, fair value 19,488 8,531
Available-for-sale securities, continuous unrealized loss position, more than twelve months, gross unrealized loss (42) (54)
Available-for-sale securities, continuous unrealized loss position, fair value 44,379 73,335
Available-for-sale securities, continuous unrealized loss position, gross unrealized loss $ (72) (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 loss   (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 loss   0
Available-for-sale securities, continuous unrealized loss position, fair value   16,241
Available-for-sale securities, continuous unrealized loss position, gross unrealized loss   $ (2)