Financial Instruments - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfer from fair value measurement level 1 to level 2	$ 0
Transfer from fair value measurement level 2 to level 1	0
Gross unrealized gains or losses for cash equivalent and marketable securities	0		$ 0
Securities that were in an unrealized loss position for more than 12 months.	$ 0		0
Gains / losses on derivative instruments		$ 0
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Foreign currency forward contracts maturity period	15 months
Foreign currency forward contracts extended maturity period	24 months
Foreign currency forward contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unrealized gain related to effective portion of changes in fair value of foreign currency forward contracts	$ 1,900,000
Reclassification from accumulated other comprehensive income into earnings over next 12 month	1,100,000
Notional value	99,900,000		60,800,000
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities within Level 3 of the fair value hierarchy	$ 0		$ 0