Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net loss	$ (73,783)	$ (343)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	13,292	12,259
Share-based compensation	20,287	13,229
Provision for doubtful accounts	150	333
Amortization of premiums on marketable securities	2,310	1,213
Deferred income tax benefit	(27,784)	(124)
Other	250	39
Change in operating assets and liabilities:
Trade and other receivables	(3,469)	566
Prepaid expenses and other current assets	(1,022)	(701)
Other non-current assets	357	716
Accounts payable	1,548	5,282
Accrued expenses and other liabilities	117,693	11,303
Deferred revenue	25,629	26,742
Other non-current liabilities	265	1,617
Net cash provided by operating activities	75,723	72,131
Investing activities
Acquisition of business, net of cash acquired	(12,797)	0
Acquisition of property and equipment, including capitalization of internal use software	(9,057)	(11,127)
Purchases of marketable securities	(191,846)	(95,686)
Sales and maturities of marketable securities	122,936	34,418
Premiums paid for company-owned life insurance policies	(4,337)	(4,337)
Net cash used in investing activities	(95,101)	(76,732)
Financing activities
Proceeds from stock-based compensation plans	10,144	9,704
Proceeds from warrant exercises	0	375
Payments for employee tax withholdings related to restricted stock units and awards	(1,793)	(760)
Net cash provided by financing activities	8,351	9,319
Net increase (decrease) in cash and cash equivalents	(11,027)	4,718
Cash and cash equivalents at beginning of period	146,569	123,911
Cash and cash equivalents at end of period	$ 135,542	$ 128,629