Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net loss	$ (806)	$ (6,351)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	2,407	2,179
Employee stock-based compensation	5,105	4,542
Impairment of assets held for sale and long-lived assets		56
Gain on disposal of property and equipment	35
Outside director restricted stock awarded in lieu of fees	50	50
Gain on sale of equity securities	(2,807)	(1,333)
Deferred tax benefit from unrealized gain on available-for-sale marketable securities, net	820	(1,107)
Changes in assets and liabilities:
Accounts receivable	586	(1,665)
Prepaid expenses and other assets	717	(480)
Accounts payable	2,218	(2,441)
Accrued compensation and employee benefits	(8,791)	(2,181)
Accrued expenses and other liabilities	1,231	3,439
Deferred revenues		(57)
Net cash provided by (used in) operating activities	765	(5,349)
Investing activities
Purchases of property and equipment	(5,144)	(5,311)
Proceeds from sale of property and equipment	10
Purchases of marketable securities	(20,599)	(12,207)
Maturities of marketable securities	13,250	19,757
Proceeds from sales of marketable securities	10,155	3,579
Net cash (used in) provided by investing activities	(2,328)	5,818
Financing activities
Net proceeds from issuance of common stock under stock plans	6,069	632
Withholding taxes related to restricted stock units net share settlement	(4,136)	(2,929)
Net cash provided by (used in) financing activities	1,933	(2,297)
Net increase (decrease) in cash and cash equivalents	370	(1,828)
Cash and cash equivalents at the beginning of the period	40,404	32,533
Cash and cash equivalents at the end of the period	40,774	30,705
Non-cash investing and financing activities
Accrued purchases of property and equipment	$ 2,486	291
Change in fair value of equity investment		$ 3,787