Acquisition-Related Amortization and Remeasurement - Components of Acquisition-Related Amortization and Remeasurement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Acquisition Related Amortization And Remeasurement [Abstract]
Changes in fair value of contingent consideration	$ (1,575)	$ 2,100	$ (75)	$ (6,900)
Amortization of acquired intangibles	1,969	1,578	3,938	2,996
Acquired IPR&D	500		1,500
Total	$ 894	$ 3,678	$ 5,363	$ (3,904)