Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net income	$ (10,389)	$ (22,861)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,488	1,871
Depreciation and amortization	378	393
Amortization of debt issuance costs and non-cash interest charges	257	257
Change in fair value of warrant liabilities	(4,527)	(410)
Change in fair value of contingent purchase consideration	1,300	(1,000)
Changes in operating assets and liabilities:
Trade accounts receivable	(3,504)	4,207
Inventory	2,586	(450)
Prepaid expenses and other current assets	(851)	(1,853)
Other assets	(2,530)	(621)
Accounts payable and accrued expenses	(4,275)	947
Deferred rent	(23)	(26)
Deferred revenue	(1,326)	(2,401)
Net cash used by operating activities	(21,416)	(21,947)
Investing activities:
Purchases of property and equipment	(83)	(54)
Net cash used by investing activities	(83)	(54)
Financing activities:
Proceeds from revolving credit facility	0	1,450
Repayment of revolving credit facility	0	(343)
Repayment of debt	(1,666)	0
Proceeds from exercise of common stock options and warrants	0	3
Net cash (used in) provided by financing activities	(1,666)	1,110
Net decrease in cash and cash equivalents	(23,165)	(20,891)
Cash and cash equivalents at beginning of period	155,349	42,205
Cash and cash equivalents at end of period	$ 132,184	$ 21,314