Fair Value Measurements - Contingent Consideration Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Contingent consideration liabilities measured at fair value
Balance at beginning of period	$ 8,267
Balance at end of period	7,107
Fair value | Level 3
Contingent consideration liabilities measured at fair value
Balance at beginning of period	8,267
Fair value adjustments included in operating expenses	(1,160)
Balance at end of period	$ 7,107