Business combinations - Summary of Business Acquisition, Pro Forma Information (Detail) - CNY (¥) ¥ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Nanjing Cuida Biotechnology Co Ltd [Member]
Business Acquisition Pro Forma Information [Line Items]
Net revenues		¥ 804,175
Net loss		(231,712)
Xingmu Group [Member]
Business Acquisition Pro Forma Information [Line Items]
Net revenues	¥ 802,249	850,932
Net loss	¥ (176,070)	¥ (230,451)

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration