Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (12,451)	$ (18,730)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	4,365	3,402
Employee stock-based compensation	9,389	8,127
Write-off of previously capitalized software costs		577
Impairment of assets held for sale and long-lived assets	56
Gain on disposal of property and equipment		(19)
Outside director restricted stock awarded in lieu of fees	100	100
Gain on sale of equity securities	(2,009)
Deferred tax benefit from unrealized gain on available-for-sale marketable securities		(6,970)
Changes in assets and liabilities:
Accounts receivable	3,553	2,016
Prepaid expenses and other assets	(1,186)	148
Accounts payable	(2,368)	(730)
Accrued compensation and employee benefits	(1,725)	290
Accrued expenses and other liabilities	4,318	919
Deferred revenues	(197)	189
Net cash provided by (used in) operating activities	1,845	(10,681)
Investing activities
Purchases of property and equipment	(6,879)	(9,508)
Purchases of marketable securities	(35,932)	(43,348)
Maturities of marketable securities	40,007	54,240
Proceeds from sales of marketable securities	5,117
Net cash provided by investing activities	2,313	1,384
Financing activities
Net proceeds from issuance of common stock under stock plans	7,072	6,894
Withholding taxes related to restricted stock units net share settlement	(3,103)	(3,572)
Net cash provided by financing activities	3,969	3,322
Net increase (decrease) in cash and cash equivalents	8,127	(5,975)
Cash and cash equivalents at the beginning of the period	32,533	29,726
Cash and cash equivalents at the end of the period	40,660	23,751
Non-cash investing and financing activities
Accrued purchase of property and equipment	605	2,870
Change in fair value of equity investment	$ (1,404)	$ 18,995