CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings/(Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Mar. 31, 2014		105,156		(16,238)
Balance at Mar. 31, 2014	$ 801,806	$ 1,052	$ 954,699	$ (276,836)	$ 120,775	$ 2,116
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(279,470)				(279,470)
Change in cumulative foreign currency translation adjustment	(32,747)					(32,747)
Change in unrealized gains on derivative instruments, net	32					32
Net unrealized loss on available-for-sale securities, net of taxes	(25)					(25)
Stock-based compensation	72,579		72,579
Tax benefit associated with stock awards	928		928
Issuance of restricted stock, net of forfeitures and cancellations (in shares)		(570)
Issuance of restricted stock, net of forfeitures and cancellations	(114)	$ (6)	(108)
Issuance of common stock in connection with acquisition (in shares)		8
Issuance of common stock in connection with acquisition	99		99
Balance (in shares) at Mar. 31, 2015		104,594		(16,238)
Balance at Mar. 31, 2015	563,088	$ 1,046	1,028,197	$ (276,836)	(158,695)	(30,624)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(8,302)				(8,302)
Change in cumulative foreign currency translation adjustment	(7,364)					(7,364)
Change in unrealized gains on derivative instruments, net	(17)					(17)
Net unrealized loss on available-for-sale securities, net of taxes	109					109
Stock-based compensation	83,137		83,137
Tax benefit associated with stock awards	1,421		1,421
Issuance of restricted stock, net of forfeitures and cancellations (in shares)		(84)
Issuance of restricted stock, net of forfeitures and cancellations	0	$ (1)	1
Repurchased common stock (in shares)				(954)
Repurchased common stock	(26,552)			$ (26,552)
Net share settlement of restricted stock awards (in shares)		(745)
Net share settlement of restricted stock awards	$ (24,135)	$ (7)	(24,128)
Balance (in shares) at Mar. 31, 2016	103,765	103,765		(17,192)
Balance at Mar. 31, 2016	$ 581,385	$ 1,038	1,088,628	$ (303,388)	(166,997)	(37,896)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	67,303				67,303
Change in cumulative foreign currency translation adjustment	(9,086)					(9,086)
Change in unrealized gains on derivative instruments, net	0
Net unrealized loss on available-for-sale securities, net of taxes	(160)					(160)
Stock-based compensation	88,378		88,378
Tax benefit associated with stock awards	1,990		1,990
Issuance of restricted stock, net of forfeitures and cancellations (in shares)		1,738
Issuance of restricted stock, net of forfeitures and cancellations		$ 17	(17)
Settlement of 1.75% Convertible Notes Due 2016 (in shares)		13,094
Settlement of 1.75% Convertible Notes Due 2016	249,997	$ 131	249,866
Conversion of 1.00% Convertible Notes Due 2018 (in shares)		899
Conversion of 1.00% Convertible Notes Due 2018	18,341	$ 9	18,332
Issuance of common stock in connection with acquisition (in shares)		1,480
Issuance of common stock in connection with acquisition	57,342	$ 15	57,327
Net share settlement of restricted stock awards (in shares)		(1,163)
Net share settlement of restricted stock awards	$ (51,762)	$ (12)	(51,750)
Balance (in shares) at Mar. 31, 2017	119,813	119,813		(17,192)
Balance at Mar. 31, 2017	$ 1,003,728	$ 1,198	$ 1,452,754	$ (303,388)	$ (99,694)	$ (47,142)