Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets:
Total assets fair value	$ 104,944	$ 139,423
Liabilities:
Contingent consideration related to acquisitions	15,008	36,220
Total liabilities fair value	15,008	36,220
Money market funds
Assets:
Cash equivalents fair value	104,944	124,303
U.S. Treasury Bills
Assets:
Cash equivalents fair value		15,120
Level 1
Assets:
Total assets fair value	104,944	139,423
Liabilities:
Contingent consideration related to acquisitions	0	0
Total liabilities fair value	0	0
Level 1 | Money market funds
Assets:
Cash equivalents fair value	104,944	124,303
Level 1 | U.S. Treasury Bills
Assets:
Cash equivalents fair value		15,120
Level 2
Assets:
Total assets fair value	0	0
Liabilities:
Contingent consideration related to acquisitions	0	0
Total liabilities fair value	0	0
Level 2 | Money market funds
Assets:
Cash equivalents fair value	0	0
Level 2 | U.S. Treasury Bills
Assets:
Cash equivalents fair value		0
Level 3
Assets:
Total assets fair value	0	0
Liabilities:
Contingent consideration related to acquisitions	15,008	36,220
Total liabilities fair value	15,008	36,220
Level 3 | Money market funds
Assets:
Cash equivalents fair value	$ 0	0
Level 3 | U.S. Treasury Bills
Assets:
Cash equivalents fair value		$ 0