Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017		Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (loss)	$ 23,083		$ (24,007)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	2,376		1,308
Stock-based compensation	13,610		15,655
Amortization of acquired intangibles	317		352
Amortization of premiums/accretion of discounts on short-term investments	(91)		136
Excess tax deficiencies from share-based compensation	0		4
Gain on sale of business	(35,871)		0
Other	(646)		(172)
Changes in operating assets and liabilities:
Accounts receivable, net	17,689		17,481
Inventory	110		(45)
Prepaid expenses and other assets	(910)		(809)
Accounts payable	(804)		(2,302)
Accrued compensation and benefits	2,265		(3,064)
Accrued and other liabilities	1,169		(169)
Severance pay (net)	295		311
Deferred revenue	(3,869)		1,398
Deferred tax assets	(227)		(95)
Net cash provided by operating activities	18,496		5,982
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales/maturities of short-term investments	28,521		22,909
Purchase of short-term investments	(51,130)		(26,285)
Proceeds from sale of business	35,015		0
Net purchases of property and equipment	(1,949)		(3,426)
Change in restricted cash	(18)		10
Net cash provided by (used in) investing activities	10,439		(6,792)
CASH FLOWS FROM FINANCING ACTIVITIES:
Settlement of holdback liability	0		(7,157)
Proceeds from issuance of common stock, net of repurchases	4,026		590
Shares withheld for tax withholding on vesting of restricted stock units	(4,632)		(2,352)
Excess tax deficiencies from share-based compensation	0		(4)
Net cash used in financing activities	(606)		(8,923)
Effect of exchange rate changes on cash and cash equivalents	646		172
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	28,975		(9,561)
CASH AND CASH EQUIVALENTS - Beginning of period	107,343	[1]	168,252
CASH AND CASH EQUIVALENTS - End of period	136,318		158,691
NONCASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment acquired but not yet paid	$ 2,205		$ 3,721

[1] The Condensed Consolidated Balance Sheet as of December 31, 2016 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.