Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities:
Net loss	$ (11,100)	$ (15,448)
Adjustments to reconcile net loss to net cash and cash equivalents provided by operating activities
Depreciation and amortization	6,973	5,110
Stock-based compensation	21,205	16,046
Benefit for deferred income taxes	(28)
Amortization of debt discount and issuance costs	5,260	4,908
Accretion of bond discount	(2,751)	(1,164)
Noncash lease expense		794
Unrealized currency translation	(281)	36
Changes in assets and liabilities
Accounts receivable	7,758	6,863
Prepaid expenses and other assets	886	1,880
Deferred commission expense	(3,334)	(5,068)
Right-of-use assets	5,505
Accounts payable	4,911	166
Accrued expenses and other liabilities	(2,071)	1,674
Lease liabilities	(4,110)
Deferred rent		(48)
Deferred revenue	8,893	10,973
Net cash and cash equivalents provided by operating activities	37,716	26,722
Investing Activities:
Purchases of investments	(386,501)	(210,886)
Maturities of investments	183,460	256,250
Purchases of property and equipment	(4,265)	(6,239)
Capitalization of software development costs	(2,821)	(2,616)
Purchases of strategic investments		(250)
Net cash and cash equivalents (used in) provided by investing activities	(210,127)	36,259
Financing Activities:
Proceeds from common stock offering, net of offering costs paid of $256	342,739
Employee taxes paid related to the net share settlement of stock-based awards	(1,084)	(2,344)
Proceeds related to the issuance of common stock under stock plans	5,690	6,113
Repayments of finance lease obligations	(118)	(212)
Net cash and cash equivalents provided by financing activities	347,227	3,557
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(784)	677
Net increase in cash, cash equivalents and restricted cash	174,032	67,215
Cash, cash equivalents and restricted cash, beginning of period	117,114	92,784
Cash, cash equivalents and restricted cash, end of period	291,146	159,999
Supplemental cash flow disclosure:
Cash paid for interest		15
Cash paid for income taxes	1,027	45
Right of use assets obtained in exchange for operating lease liabilities	12,410
Non-cash investing and financing activities:
Common stock offering costs, incurred but not yet paid	109
Capital expenditures incurred but not yet paid	$ 2,802	1,382
Asset retirement obligations		$ 101