Fair Value Measurements - Contingent Consideration Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Contingent consideration liabilities measured at fair value
Balance at beginning of period	$ 12,485
Balance at end of period	7,587
Fair value | Level 3
Contingent consideration liabilities measured at fair value
Balance at beginning of period	12,485
Fair value adjustments included in operating expenses	(4,898)
Balance at end of period	$ 7,587