Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss		$ (12,269)	$ (28,223)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization		20,034	16,219
Accretion of debt discount and amortization of debt issuance costs		2,543	6,922
Purchased investment premium, net of amortization		(725)	(187)
Net foreign currency (gain) loss		1,115	(1,685)
Stock-based compensation expense		36,196	35,511
Changes in operating assets and liabilities:
Accounts receivable		21,874	43,095
Deferred commissions		(8,730)	(2,740)
Prepaid expenses and other assets		6,954	(16,823)
Accounts payable		1,606	(7,855)
Accrued expenses		(9,719)	(1,366)
Deferred revenue		(32,574)	(27,883)
Other liabilities		2,172	(2,337)
Net cash provided by operating activities		28,477	12,648
Cash flows from investing activities:
Purchases of investments		(82)	484
Maturities of investments		197,774	72,689
Capital expenditures		(9,274)	(7,627)
Capitalized software costs		(14,127)	(12,302)
Net cash provided by investing activities		174,291	53,244
Cash flows from financing activities:
Payments of debt issuance costs		0	(152)
Payment of tax withholdings for employee stock plans		(5,469)	0
Proceeds from employee stock plans		14,211	30,047
Repurchases of common stock		0	(38,608)
Net cash provided by (used in) financing activities		8,742	(8,713)
Effect of exchange rate changes on cash and cash equivalents		0	176
Net increase in cash and cash equivalents		211,510	57,355
Cash and cash equivalents at beginning of period		183,596	393,576
Cash and cash equivalents at end of period		395,106	450,931
Supplemental cash flow information:
Cash paid for interest		8,731	5,003
Cash paid for income taxes		970	874
Proceeds from employee stock plans received in advance of stock issuance		720	499
Cash paid for operating leases1	[1]	5,700	0
Right-of-use assets obtained in exchange for lease obligations1	[1]	86,120	0
Non-cash investing and financing activities:
Assets acquired under capital leases and other financing arrangements		1,702	0
Capitalized assets financed by accounts payable and accrued expenses		2,728	3,577
Capitalized stock-based compensation		$ 2,113	$ 2,451

[1] See Note 1 for additional information.