Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net loss	$ (14,134)	$ (17,475)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	6,690	7,964
Stock-based compensation	7,509	11,288
Change in deferred taxes	(5)	63
Non-recurring gain	0	(1,107)
Other	74	0
Decrease (increase) in:
Accounts receivable, net	20,168	20,043
Prepaid expenses and other assets	1,671	(341)
Increase (decrease) in:
Accounts payable	(255)	2,457
Accrued payroll and related liabilities	1,966	519
Other accrued liabilities	(2,509)	(1,650)
Deferred revenue	(21,869)	(12,648)
Other long-term liabilities	(169)	279
Net cash provided by (used in) operating activities	(863)	9,392
Cash flows from investing activities:
Payments for purchase of property and equipment	(1,647)	(3,343)
Purchases of marketable securities	(39,424)	(57,757)
Sales of marketable securities	1,001	11,302
Maturities of marketable securities	43,398	39,802
Net cash provided by (used in) investing activities	3,328	(9,996)
Cash flows from financing activities:
Proceeds from exercise of stock options	305	788
Taxes paid related to net share settlement of equity awards	(375)	(595)
Capital lease payments	(31)	0
Repayments of term loans	(1,200)	(1,200)
Non-recurring gain	0	1,107
Net cash provided by (used in) financing activities	(1,301)	100
Net increase (decrease) in cash and cash equivalents	1,164	(504)
Effect of exchange rate changes	28	(47)
Cash and cash equivalents, beginning of period	9,870	20,594
Cash and cash equivalents, end of period	$ 11,062	$ 20,043