Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (38,354)	$ (46,084)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	17,306	13,356
Stock-based compensation expense	29,778	23,719
Other	498	822
Changes in operating assets and liabilities:
Accounts receivable	9,223	(6,478)
Prepaid expenses and other assets	(4,438)	(1,651)
Accounts payable	(829)	1,125
Accrued compensation and benefits and other liabilities	2,475	3,307
Deferred revenue	8,938	18,169
Deferred rent	(504)	3,052
Net cash provided by operating activities	24,093	9,337
Cash flows from investing activities:
Purchases of property and equipment	(17,577)	(16,601)
Increase in restricted cash	(87)	0
Purchases of short-term investments	(78,074)	(116,285)
Proceeds from sale and maturity of short-term investments	88,232	126,113
Capitalized software development costs	(3,054)	(3,075)
Net cash used in investing activities	(10,560)	(9,848)
Cash flows from financing activities:
Proceeds from employee stock purchase plan	3,029	2,504
Proceeds from exercise of employee stock options	20,370	12,263
Net cash provided by financing activities	23,399	14,767
Net increase in cash and cash equivalents	36,932	14,256
Cash and cash equivalents, beginning of period	88,305	65,914
Cash and cash equivalents, end of period	125,237	80,170
Supplemental disclosure of cash flow information:
Cash paid for interest and income taxes	358	226
Noncash investing and financing activities:
Property and equipment purchased but not yet paid	$ 256	$ 2,534