Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Benefit plans (Details) - USD ($) $ in Thousands	12 Months Ended
Benefit plans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
401(k) Plan
Benefit Plans
Contributions to the plan	$ 232	$ 102	$ 49
Pension Plan
Benefit Plans
Maximum percentage of contribution by employee of their annual base salary	8.00%