5. INCOME TAXES - Unrecognized tax benefits (Details) - USD ($)	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017
INCOME TAXES
Unrecognized tax benefits, current	$ 0		$ 0
Unrecognized tax benefits, noncurrent	247,000		244,000
Deferred tax assets unrecognized tax benefit	2,600,000
Possible reduction in uncertain tax benefits	0
Net deferred tax assets	$ 10,400,000		$ 8,900,000
Effective annual income tax rate (as a percentage)	9.90%	7.00%