Investments - Additional Information (Detail)	6 Months Ended
Sep. 30, 2020
Minimum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Treasury with original maturities period	3 months
Maximum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investment maturity date range end	Dec. 24, 2020
Treasury with original maturities period	1 year

Maturity date of investment, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

Name:	us-gaap_InvestmentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	instant