Fair Value Measurements (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and cash equivalents	$ 143,235	$ 135,823
Short-term investments	19,304
Significant Unobservable Inputs (Level 3)
Liabilities
Contingent consideration	1,252
Amount Recorded on Balance Sheet
Assets
Cash and cash equivalents	143,235	$ 135,823
Short-term investments	19,304
Liabilities
Contingent consideration	$ 1,252