Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net loss	$ (18,498,000)	$ (21,698,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	594,000	447,000
Loss on disposal of equipment	47,000
Share-based compensation	1,125,000	466,000
Noncash interest expense	4,068,000	546,000
Change in estimated fair value of financial instruments	(6,717,000)	7,053,000
Gain on extinguishment of debt	(49,000)
Amortization of investment securities premiums/discounts, net	4,000
Net changes in operating assets and liabilities:
Accounts receivable	920,000	(52,000)
Inventories	(5,882,000)	(2,362,000)
Prepaid expenses and other current assets	(1,413,000)	(52,000)
Other assets	1,922,000	(1,784,000)
Accounts payable	3,021,000	1,485,000
Accrued liabilities	(50,000)	(157,000)
Deferred revenue	527,000	792,000
Other liabilities	(37,000)	(15,000)
Net cash used in operating activities	(20,418,000)	(15,331,000)
Cash flows from investing activities
Purchases of property, plant and equipment	(2,238,000)	(2,149,000)
Proceeds from sale of equipment	16,000
Purchase of short-term investments	(12,688,000)
Maturities of short-term investments		2,000,000
Net cash used in investing activities	(14,910,000)	(149,000)
Cash flows from financing activities
Proceeds from initial public offering, net of offering costs and underwriter commissions	56,105,000
Proceeds from issuance of convertible notes payable	6,529,000	8,075,000
Proceeds from issuance of debt	3,700,000	9,875,000
Proceeds from line of credit		500,000
Repayment of line of credit		(500,000)
Repayment of debt	(9,367,000)	(708,000)
Repayment of capital leases	(162,000)	(122,000)
Proceeds from secured borrowing	2,880,000
Reductions in secured borrowing	(2,880,000)
Change in restricted cash	9,139,000
Proceeds from exercise of stock options	81,000	22,000
Proceeds from exercise of preferred stock warrants	47,000
Proceeds from exercise of common stock warrants	25,000
Net cash provided by financing activities	66,097,000	17,142,000
Net increase in cash and cash equivalents	30,769,000	1,662,000
Cash and cash equivalents, beginning of year	10,006,000	2,215,000
Cash and cash equivalents, end of period	40,775,000	3,877,000
Supplemental disclosure of cash flow information
Cash paid for interest, net of capitalized interest of $450 and $43 for the nine months ended September 30, 2013 and 2012, respectively.	1,321,000	703,000
Supplemental disclosure of noncash investing and financing activities
Equipment acquired under capital leases	617,000	102,000
Interest added to the principal of convertible notes	1,623,000
Reclassification of warrants from liabilities to equity	2,669,000
Conversion of convertible notes to common stock	44,890,000
Conversion of preferred stock to common stock	$ 39,659,000