Stock Option Activity (Detail) - $ / shares	6 Months Ended	12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017
Shares
Beginning balance	1,165,350
Granted	80,000
Exercised	0
Cancelled/expired	(33,000)
Ending balance	1,212,350	1,165,350
Vested and exercisable	1,040,840
Weighted Average Per Share Exercise Price
Beginning balance	$ 4.24
Granted	9.71
Exercised	0
Cancelled/expired	9.62
Ending balance	4.42	$ 4.24
Vested and exercisable	$ 4.04
Weighted Average Remaining Life (Years)
Balance	6 years 4 months 10 days	6 years 7 months 20 days
Granted	0 years
Exercised	0 years
Cancelled/expired	0 years
Vested and exercisable	5 years 11 months 1 day
Weighted Average Per Share Intrinsic Value
Beginning Balance	$ 4.86
Granted	0
Exercised	0
Cancelled/expired	0
Ending balance	5.35	$ 4.86
Vested and exercisable	$ 5.74