Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating Activities
Net loss	$ (20,327)	$ (11,694)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation and amortization	1,064	1,444
Amortization of debt issuance costs	78	23
Remeasurement of fair value of preferred stock warrant liability	1,800	0
Accretion/amortization of bond discount/premium	(1)	1
Stock-based compensation	484	274
Gain on disposal of property and equipment	32	4
Impairment loss on property and equipment	304	0
Changes in operating assets and liabilities:
Accounts receivable	251	(232)
Interest receivable	6	(62)
Inventory	667	(282)
Other current and long term assets	(527)	(122)
Accounts payable	1,444	(351)
Related party payable	173	(10)
Accrued expenses	505	125
Net cash and cash equivalents used in operating activities	(14,047)	(10,901)
Investing Activities
Purchase of investments	(1,104)	(4,702)
Proceeds from sale and maturities of investments	907	0
Cash received in acquisition of a business, net of cash paid	305	0
Purchase of property and equipment	(724)	(92)
Proceeds from sale of property and equipment	0	49
Net cash and cash equivalents used in investing activities	(616)	(4,745)
Financing Activities
Proceeds from issuance of debt	1,998	4,000
Payment of debt	(601)	0
Proceeds from issuance of preferred stock, net of issuance costs	28,199	268
Proceeds from exercise of stock options	0	3
Net cash and cash equivalents provided by financing activities	29,596	4,271
Net increase (decrease) in cash and cash equivalents	14,933	(11,375)
Cash and Cash Equivalents, beginning of period	8,896	14,004
Cash and Cash Equivalents, end of period	23,829	2,629
Supplemental Disclosure for Cash Flow Information
Interest paid	625	219
Supplemental Schedule of Noncash Investing and Financing Activities
Issuance of preferred stock warrants and debt issuance costs	128	63
Conversion of bridge notes to preferred stock	1,998	0
Conversion of preferred stock warrants to common stock warrants	$ 1,909	$ 0