Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Assets fair value	$ 119,975	$ 139,423
Liabilities:
Liabilities fair value	9,680	36,220
Contingent Consideration
Liabilities:
Liabilities fair value	9,680	36,220
Cash Equivalents | Money Market Funds
Assets:
Assets fair value	104,790	124,303
Cash Equivalents | U.S. Treasury Bills
Assets:
Assets fair value	15,185	15,120
Level 1
Assets:
Assets fair value	119,975	139,423
Level 1 | Cash Equivalents | Money Market Funds
Assets:
Assets fair value	104,790	124,303
Level 1 | Cash Equivalents | U.S. Treasury Bills
Assets:
Assets fair value	15,185	15,120
Level 3
Liabilities:
Liabilities fair value	9,680	36,220
Level 3 | Contingent Consideration
Liabilities:
Liabilities fair value	$ 9,680	$ 36,220