Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income		$ (9,781)	$ 23,083
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Net cash provided by operating activities		22,502	18,496
Depreciation and amortization		3,111	2,376
Amortization of deferred costs		1,041	0
Stock-based compensation		14,637	13,610
Amortization of acquired intangibles		132	317
Amortization of premiums/accretion of discounts on short-term investments		(387)	(91)
Gain on sale of business		0	(35,871)
Other adjustments		34	(646)
Changes in operating assets and liabilities:
Accounts receivable, net		16,317	17,689
Inventory		439	110
Deferred costs		(3,626)	0
Prepaid expenses and other assets		(1,529)	(910)
Accounts payable		497	(804)
Accrued compensation and benefits		1,963	2,265
Accrued and other liabilities		(399)	1,169
Severance pay (net)		214	295
Deferred revenue		700	(3,869)
Deferred tax assets		(861)	(227)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales/maturities of short-term investments		11,704	28,521
Purchase of short-term investments		(9,255)	(51,130)
Proceeds from sale of business		0	35,015
Net purchases of property and equipment		(2,792)	(1,949)
Net cash (used in) provided by investing activities		(343)	10,457
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net of repurchases		5,293	4,026
Shares withheld for tax withholding on vesting of restricted stock units		(5,671)	(4,632)
Net cash used in financing activities		(378)	(606)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash		2	646
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH		21,783	28,993
CASH, CASH EQUIVALENTS AND RESTRICTED CASH - Beginning of period	[1]	194,874	109,295
CASH, CASH EQUIVALENTS AND RESTRICTED CASH - End of period	[1]	216,657	138,288
NONCASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment acquired but not yet paid		$ 233	$ 2,205

[1] Amounts in As Reported column include cash, cash equivalents and restricted cash as required. Amounts in the As Previously Reported column reflect only cash and cash equivalents.