5. INCOME TAXES - Unrecognized tax benefits (Details) - USD ($)	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017
INCOME TAXES
Unrecognized tax benefits, current	$ 0		$ 0
Unrecognized tax benefits, noncurrent	249,000		244,000
Deferred tax assets unrecognized tax benefit	2,600,000
Possible reduction in uncertain tax benefits	0
Net deferred tax assets	$ 10,800,000		$ 8,900,000
Effective annual income tax rate (as a percentage)	(11.80%)	23.50%