Goodwill and Acquired Intangible Assets - Acquired Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Cost	$ 15,800	$ 15,800
Accumulated Amortization	(4,706)	(3,739)
Foreign Currency Translation Adjustments	(190)	(357)
Net	10,904	11,704
Developed Technology
Finite Lived Intangible Assets [Line Items]
Cost	14,000	14,000
Accumulated Amortization	(3,991)	(3,133)
Foreign Currency Translation Adjustments	(147)	(279)
Net	$ 9,859	$ 10,587
Remaining Useful Life	3 years 6 months	3 years 8 months 12 days
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Cost	$ 1,800	$ 1,800
Accumulated Amortization	(715)	(606)
Foreign Currency Translation Adjustments	(43)	(78)
Net	$ 1,045	$ 1,117
Remaining Useful Life	2 years 9 months 18 days	3 years 1 month 6 days