Note 11 - Employee Equity Incentive Plans - Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
		Sep. 30, 2016	Mar. 31, 2016
Options outstanding, beginning of period (in shares)		5,234,397
Weighted average exercise price per share, beginning balance (in dollars per share)		$ 10.40
Options oustanding, Options granted (in shares)		387,000
Weighted average exercise price per share, Options granted (in dollars per share)		$ 11.23
Options oustanding, Options exercised (in shares)		(105,997)
Weighted average exercise price per share, Options exercised (in dollars per share)		$ 7.95
Options exercised, Intrinsic Value	[1]	$ 375
Options oustanding, Options cancelled (in shares)		(7,500)
Weighted average exercise price per share, Options cancelled (in dollars per share)		$ 13.37
Options oustanding, Options expired (in shares)		(5,000)
Weighted average exercise price per share, Options expired (in dollars per share)		$ 9.73
Options oustanding, ending balance (in shares)		5,502,900
Weighted average exercise price per share, ending balance (in dollars per share)		$ 10.50
Options exercisable (in shares)		3,950,650	3,619,563
Weighted average exercise price per share, exercisable (in dollars per share)		$ 10.12	$ 9.93

[1] Represents the difference between the exercise price and the value of our common stock at the time of exercise.