Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities
Net loss	$ (15,271)	$ (30,573)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	6,654	5,076
Employee stock-based compensation	14,102	12,055
Write-off of previously capitalized software costs	2,600	635
Impairment of assets held for sale	56
Gain on disposal of property and equipment	(158)	(61)
Outside director restricted stock awarded in lieu of fees	150	150
Gain on sale of equity securities	(2,009)
Deferred tax benefit from unrealized gain on available-for-sale marketable securities	(349)	(765)
Changes in assets and liabilities:
Accounts receivable	3,482	1,162
Prepaid expenses and other assets	(1,456)	(383)
Accounts payable	(1,970)	(1,816)
Accrued compensation and employee benefits	2,436	3,096
Accrued expenses and other liabilities	2,777	1,863
Deferred revenues	(403)	(84)
Net cash provided by (used in) operating activities	10,641	(9,645)
Investing activities
Purchases of property and equipment	(8,788)	(16,056)
Proceeds from sale of property and equipment	8	42
Purchases of marketable securities	(56,504)	(54,605)
Maturities of marketable securities	51,257	74,505
Proceeds from sales of marketable securities	5,117
Other investments	(6,100)
Net cash provided by investing activities	(15,010)	3,886
Financing activities
Net proceeds from issuance of common stock under stock plans	9,105	7,766
Withholding taxes related to restricted stock units net share settlement	(3,270)	(3,723)
Net cash provided by financing activities	5,835	4,043
Net increase (decrease) in cash and cash equivalents	1,466	(1,716)
Cash and cash equivalents at the beginning of the period	32,533	29,726
Cash and cash equivalents at the end of the period	33,999	28,010
Non-cash investing and financing activities
Accrued purchase of property and equipment	3,802	4,128
Change in fair value of equity investment	$ 942	$ 2,083