Revenue Recognition - Schedule of Deferred Revenues Balance as of Transition Date and Significant Activity Affecting Deferred Revenues (Detail)	6 Months Ended
	Sep. 30, 2020 USD ($)
Change In Contract With Customer Liability [Abstract]
Beginning balance at April 1, 2020 (Note 8)	$ 17,645,000
Additions	18,255,000
Revenue recognized from beginning of period	(5,084,000)
Revenue recognized from additions	(10,350,000)
Ending balance at September 30, 2020 (Note 8)	$ 20,466,000