Acquisition-Related Amortization and Remeasurement - Components of Acquisition-Related Amortization and Remeasurement (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Acquisition Related Amortization And Remeasurement [Abstract]
Changes in fair value of contingent consideration	$ (2,300)	$ (700)	$ (2,375)	$ (7,600)
Amortization of acquired intangibles	1,965	1,838	5,903	4,834
Acquired IPR&D			1,500
Total	$ (335)	$ 1,138	$ 5,028	$ (2,766)