STOCK-BASED COMPENSATION: Stock options outstanding and exercisable (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stock options outstanding and exercisable by exercise price range
Options outstanding (in shares)	1,394,264
Options outstanding - Weighted-average remaining contractual life	3 years 10 months 24 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 14.21
Options exercisable (in shares)	1,281,248
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 15.31
Range of exercise price per share from $0.61 to $9.99
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	0.61
Exercise price per share, high end of range (in dollars per share)	$ 9.99
Options outstanding (in shares)	264,245
Options outstanding - Weighted-average remaining contractual life	5 years 9 months 18 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 1.60
Options exercisable (in shares)	151,229
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 1.52
Range of exercise price per share from $10.00 to $19.99
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	10.00
Exercise price per share, high end of range (in dollars per share)	$ 19.99
Options outstanding (in shares)	709,672
Options outstanding - Weighted-average remaining contractual life	2 years 9 months 18 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 14.69
Options exercisable (in shares)	709,672
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 14.69
Range of exercise price per share from $20.00 to $24.99
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	20.00
Exercise price per share, high end of range (in dollars per share)	$ 24.99
Options outstanding (in shares)	420,347
Options outstanding - Weighted-average remaining contractual life	4 years 7 months 6 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 21.32
Options exercisable (in shares)	420,347
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 21.32
Stock options
Stock options outstanding and exercisable by exercise price range
Share-based compensation expense	$ 2.8	$ 2.6
Share-based compensation not yet recognized	$ 4.6