OTHER FINANCIAL INFORMATION (Schedule of Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Condensed Income Statements, Captions [Line Items]
Total interest expense	$ 5,134	$ 2,573	$ 11,566	$ 7,658
2020 Convertible Notes [Member]
Condensed Income Statements, Captions [Line Items]
Stated interest	498	701	1,810	2,106
Amortization of note discount	1,254	1,661	4,482	4,924
Amortization of debt issue costs	158	211	552	627
Interest expense on convertible notes	1,910	2,573	6,844	7,657
2025 Convertible Notes [Member]
Condensed Income Statements, Captions [Line Items]
Stated interest	1,150		1,661
Amortization of note discount	1,903		2,742
Amortization of debt issue costs	141		203
Interest expense on convertible notes	3,194		4,606
Other interest expense	30		116	1
Total interest expense	$ 5,134	$ 2,573	$ 11,566	$ 7,658