Revenue Recognition - Schedule of Disaggregated Revenue by Major Business Line (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Disaggregation Of Revenue [Table]
Total revenue	$ 164,850	$ 207,666
U.S.
Disaggregation Of Revenue [Table]
Total revenue	134,725	175,486
International
Disaggregation Of Revenue [Table]
Total revenue	30,125	32,180
Impella Product
Disaggregation Of Revenue [Table]
Total revenue	155,417	199,864
Service and Other
Disaggregation Of Revenue [Table]
Total revenue	$ 9,433	$ 7,802