CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net loss	$ (23,521)	$ (23,806)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	595	772
Losses (gains) on sales of fixed assets	259	(217)
Expenses for share-based compensation awards	2,099	4,796
Changes in assets and liabilities:
Decrease (increase) in accounts receivable	5,744	(580)
Decrease (increase) in other current assets	812	(106)
(Decrease) in accounts payable and accrued expenses	(2,508)	(2,348)
(Decrease) in deferred revenue - current	(780)	0
(Decrease) in deferred revenue - long term	0	(102)
(Decrease) in other liabilities	(163)	(498)
Net cash used in operating activities	(17,463)	(22,089)
Cash flows from investing activities:
Cash acquired in acquisition of subsidiary	1,888	0
Capital expenditures	(47)	(731)
Proceeds from sales of fixed assets	104	263
Proceeds from redemption of auction rate securities	1,100	100
Net cash provided by (used in) investing activities	3,045	(368)
Cash flows from financing activities:
Equity issuance costs in connection with acquisition of subsidiary	(45)	0
Proceeds from public offering of common stock net of underwriting discounts and commissions and offering expenses	34,843	0
Proceeds from the exercise of stock options	3	172
Net cash provided by financing activities	34,801	172
Net increase (decrease) in cash and cash equivalents	20,383	(22,285)
Cash and cash equivalents at beginning of period	58,838	70,105
Cash and cash equivalents at end of period	79,221	47,820
Supplemental disclosure of cash flow information:
Acquisition-related contingent consideration liability	15,900	0
Stock acquisition consideration	$ 11,265	$ 0