CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated other Comprehensive Income (Loss)	Accumulated Deficit	Total
Beginning balance, amount at Mar. 31, 2015	$ 88	$ 378,971	$ (2,109)	$ (104,739)	$ 272,211
Beginning balance, shares at Mar. 31, 2015	88,065,528
Issuance of common stock under stock plans	$ 2	5,386	0	0	5,388
Issuance of common stock under stock plans, shares	2,218,470
Withholding taxes from stock plans	$ 0	(466)	0	0	(466)
Withholding taxes from stock plans, shares	(30,702)
Issuance of common stock for acquisition of businesses, net of issuance costs	$ 0	0	0	0	0
Issuance of common stock for acquisition of businesses, net of issuance costs, shares	352,044
Repurchase of common stock	$ (1)	(11,189)	0	0	(11,190)
Repurchase of common stock, shares	(1,392,135)
Stock-based compensation expense	$ 0	16,334	0	0	16,334
Income tax benefit from stock-based compensation	0	224	0	0	224
Unrealized investment gain (loss)	0	0	(50)	0	(50)
Foreign currency translation adjustment	0	0	(2,025)	0	(2,025)
Net loss	0	0	0	(5,120)	(5,120)
Ending balance, amount at Mar. 31, 2016	$ 89	389,260	(4,184)	(109,859)	275,306
Ending balance, shares at Mar. 31, 2016	89,213,205
Issuance of common stock under stock plans	$ 3	4,557	0	0	4,560
Issuance of common stock under stock plans, shares	2,576,785
Withholding taxes from stock plans	$ (1)	(3,003)	0	0	(3,004)
Withholding taxes from stock plans, shares	(289,899)
Stock-based compensation expense	$ 0	21,462	0	0	21,462
Income tax benefit from stock-based compensation	0	486	0	0	486
Unrealized investment gain (loss)	0	0	70	0	70
Foreign currency translation adjustment	0	0	(5,528)	0	(5,528)
Net loss	0	0	0	(4,751)	(4,751)
Ending balance, amount at Mar. 31, 2017	$ 91	412,762	(9,642)	(114,610)	288,601
Ending balance, shares at Mar. 31, 2017	91,500,091
Adjustment from adoption of ASU 2016-9 | Update 201609				17,643
Adjustment from adoption of ASU 2016-9	$ 0	0	0		17,643
Issuance of common stock under stock plans, less withholding taxes	$ 3	2,179	0	0	2,182
Issuance of common stock under stock plans, less withholding taxes,shares	2,709,990
Repurchase of common stock	$ (1)	(17,933)	0	0	(17,934)
Repurchase of common stock, shares	(1,362,727)
Stock-based compensation expense	$ 0	28,782	0	0	28,782
Income tax benefit from stock-based compensation					0
Unrealized investment gain (loss)	0	0	(259)	0	(259)
Foreign currency translation adjustment	0	0	4,256	0	4,256
Net loss	0	0	0	(104,497)	(104,497)
Ending balance, amount at Mar. 31, 2018	$ 93	$ 425,790	$ (5,645)	$ (201,464)	$ 218,774
Ending balance, shares at Mar. 31, 2018	92,847,354