6. INCOME TAXES - Unrecognized tax benefits (Details) - USD ($)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
INCOME TAXES
Unrecognized tax benefits, noncurrent	$ 622,000	$ 619,000
Deferred tax assets unrecognized tax benefit	2,500,000	2,100,000
Deferred tax assets, gross	6,737,000	5,988,000
Net deferred tax assets	35,000	75,000
Less valuation allowance	(6,700,000)	(5,913,000)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of period	2,735,000	2,714,000	$ 2,055,000
Additions based on tax positions related to current year	371,000	520,000	730,000
Additions based on tax positions related to prior years	13,000
2017 Tax Act and tax rate re-measurement		(499,000)
Reductions based on tax positions related to prior years	(17,000)
Lapses during the current year applicable to statutes of limitations			(71,000)
Unrecognized tax benefits, end of period	3,102,000	$ 2,735,000	$ 2,714,000
Unrecognized tax benefit that would impact effective tax rate	$ 599,000