Allowance for doubtful accounts (Details Narrative) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Allowance For Doubtful Accounts Details Narrative
Balance due from doubtfull account holder	$ 0	$ 0

Amount of increase (decrease) in valuation and qualifying accounts and reserves.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

Name:	us-gaap_ValuationAllowancesAndReservesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration