Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net loss	$ (67,487)	$ (50,149)	$ (40,225)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	15,119	9,044	4,536
Stock-based compensation expense	23,268	11,666	6,220
Other	2,420	36	943
Changes in operating assets and liabilities, net of acquisition of business:
Accounts receivable, net	(19,456)	(8,565)	(3,036)
Prepaid expenses and other assets	(1,834)	(1,449)	(754)
Accounts payable	(774)	1,012	2,284
Accrued compensation and benefits and other liabilities	7,205	4,790	2,069
Deferred revenue	45,414	18,948	5,388
Deferred rent	131	1,046	1,862
Net cash provided by (used in) operating activities	4,006	(13,621)	(20,713)
Cash flows from investing activities:
Purchases of property and equipment	(11,732)	(12,628)	(9,758)
Down payment for property and equipment			(1,269)
Acquisition of business, net of cash acquired	(5,498)	(2,262)
Decrease (increase) in restricted cash	(3,492)	978	(1,001)
Purchases of short-term investments	(110,978)	(114,468)
Proceeds from sale and maturity of short-term investments	80,397	18,717
Capitalized software development costs	(6,748)	(9,017)	(5,199)
Net cash used in investing activities	(58,051)	(118,680)	(17,227)
Cash flows from financing activities:
Proceeds from issuances of preferred stock, net of issuance costs		97,243
Proceeds from initial public offering, net of issuance costs		119,924
Principal payments on debt		(271)
Proceeds from employee stock purchase plan	2,243
Proceeds from issuance of common stock	12,459	1,209	294
Net cash provided by financing activities	14,702	218,105	294
Net increase (decrease) in cash and cash equivalents	(39,343)	85,804	(37,646)
Cash and cash equivalents, beginning of period	105,257	19,453	57,099
Cash and cash equivalents, end of period	65,914	105,257	19,453
Supplemental disclosure of cash flow information:
Cash paid for interest and income taxes	169	91	52
Noncash investing and financing activities:
Issuance of common stock for the acquisition of business	6,777	1,826
Conversion and net exercise of preferred stock warrants		632
Net exercise of preferred stock warrants in connection with the initial public offering		280
Property and equipment purchased but not paid yet	$ 828	$ 464	619
Accrued initial public offering costs			$ 237