STOCKHOLDERS' EQUITY: (Details 3) (USD $)	12 Months Ended
	Mar. 31, 2015
Stock options outstanding and exercisable by exercise price range
Options outstanding (in shares)	4,893,046
Options outstanding - Weighted-average remaining contractual life	4 years 8 months 23 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 15.11
Options exercisable (in shares)	3,152,866
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 17.74
Range of exercise price per share from $0.63 to $8.90
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 0.63
Exercise price per share, high end of range (in dollars per share)	$ 8.90
Options outstanding (in shares)	1,082,710
Options outstanding - Weighted-average remaining contractual life	7 years 5 months 1 day
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 1.66
Options exercisable (in shares)	257,094
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 2.33
Range of exercise price per share from $11.08 to $14.42
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 11.08
Exercise price per share, high end of range (in dollars per share)	$ 14.42
Options outstanding (in shares)	1,483,096
Options outstanding - Weighted-average remaining contractual life	4 years 11 months 5 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 13.16
Options exercisable (in shares)	1,130,735
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 13.07
Range of exercise price per share from $15.10 to $19.76
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 15.10
Exercise price per share, high end of range (in dollars per share)	$ 19.76
Options outstanding (in shares)	577,388
Options outstanding - Weighted-average remaining contractual life	2 years 3 months 26 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 16.32
Options exercisable (in shares)	543,258
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 16.14
Range of exercise price per share from $20.44 to $24.53
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 20.44
Exercise price per share, high end of range (in dollars per share)	$ 24.53
Options outstanding (in shares)	1,419,424
Options outstanding - Weighted-average remaining contractual life	4 years 4 months 2 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 22.23
Options exercisable (in shares)	906,016
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 22.77
Range of exercise price per share from $26.33 to $35.16
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 26.33
Exercise price per share, high end of range (in dollars per share)	$ 35.16
Options outstanding (in shares)	200,049
Options outstanding - Weighted-average remaining contractual life	1 year 1 month 6 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 30.84
Options exercisable (in shares)	185,384
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 30.68
Range of exercise price per share from $41.38 to $62.06
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 41.38
Exercise price per share, high end of range (in dollars per share)	$ 62.06
Options outstanding (in shares)	130,379
Options outstanding - Weighted-average remaining contractual life	4 months 21 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 41.83
Options exercisable (in shares)	130,379
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 41.83