CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013
Operating activities
Net loss	$ (18,573)		$ (37,477)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	989		410
Stock-based compensation	3,764		2,415
Changes in revaluation of warrant liability	(14,263)		16,803
Non-cash interest expense	65		0
Deferred income taxes	19		20
Loss on disposal of fixed assets	3		96
Changes in operating assets and liabilities:
Accounts receivable	(1,241)		(2,581)
Inventories	(632)		(1,345)
Other assets	(2,860)		154
Accounts payable	(1,555)		(3,110)
Accrued liabilities	2,728		4,448
Deferred revenue	379		34
Net cash used in operating activities	(31,177)		(20,133)
Investing activities
Capital expenditures	(2,033)		(440)
Purchases of investments	(14,807)		(29,162)
Proceeds from maturities of investments	17,305		0
Proceeds from sales (purchases) of certain assets and other	50		(14)
Net cash provided by (used in) investing activities	515		(29,616)
Financing activities
Net proceeds from equity incentives and exercise of warrants	10,269		595
Net proceeds from public offering	6,849		50,981
Proceeds from term loan, net of discount and revolving line of credit	9,848		2,008
Payments on debt, revolving line of credit and landlord provided leasehold incentives	(3,446)		(6,176)
Net cash provided by financing activities	23,520		47,408
Net decrease in cash and cash equivalents	(7,142)		(2,341)
Cash and cash equivalents, beginning of period	29,485	[1]	26,696
Cash and cash equivalents, end of period	$ 22,343		$ 24,355

[1] The financial information in this column was derived from audited financial statements included in the Company's 2013 Annual Report on Form 10-K.