Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (60,461)		$ (43,101)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,107		3,337
Stock-based compensation	45,736		38,801
Amortization of acquired intangibles	1,056		1,056
Loss on disposals	267		0
Amortization of premiums/accretion of discounts on short-term investments	144		398
Excess tax deficiencies (benefits) from share-based compensation	29		(60)
Other	(265)		0
Changes in operating assets and liabilities:
Accounts receivable, net	15,349		5,960
Inventory	40		(683)
Prepaid expenses and other assets	549		(1,760)
Accounts payable	(2,089)		(964)
Accrued compensation and benefits	(2,360)		571
Accrued and other liabilities	515		1,187
Severance pay (net)	315		356
Deferred revenue	9,893		10,116
Deferred tax assets	(183)		(26)
Net cash provided by operating activities	13,642		15,188
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales/maturities of short-term investments	54,916		20,721
Purchase of short-term investments	(107,403)		(75,399)
Net purchases of property and equipment	(13,953)		(4,038)
Change in restricted cash	10		(12)
Net cash used in investing activities	(66,430)		(58,728)
CASH FLOWS FROM FINANCING ACTIVITIES:
Settlement of holdback liability	(7,157)		0
Proceeds from follow-on public offering, net of offering costs	0		127,853
Offering costs relating to follow-on public offering	(112)		0
Proceeds from issuance of common stock, net of repurchases	8,106		12,668
Shares withheld for tax withholding on vesting of restricted stock units	(6,520)		(7,221)
Excess tax (deficiencies) benefits from share-based compensation	(29)		60
Net cash (used in) provided by financing activities	(5,712)		133,360
Effect of exchange rate changes on cash and cash equivalents	265		33
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(58,235)		89,853
CASH AND CASH EQUIVALENTS - Beginning of period	168,252	[1]	68,096
CASH AND CASH EQUIVALENTS - End of period	110,017		157,949
NONCASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment incurred but not yet paid	295		132
Vesting of restricted and early exercised stock options	$ 0		$ 767

[1] The Condensed Consolidated Balance Sheet as of December 31, 2015 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.