Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net loss	$ (35,219)	$ (27,404)
Depreciation	212	167
Accretion of debt discount	198	278
Amortization of intangible assets	485	485
Derivative loss	114
Stock-based compensation expense	7,457	7,658
Changes in assets and liabilities:
Accounts receivable	80	1,614
Inventories	(1,868)	295
Prepaid expenses and other assets	321	133
Accounts payable and accrued expenses	(441)	(2,210)
Deferred revenue	90	(366)
Net cash flows from operating activities	(28,571)	(19,350)
Investing activities:
Purchase of equipment	(249)	(583)
Net cash flows from investing activities	(249)	(583)
Financing activities:
Proceeds from issuance of common stock	2,459
Equity financing costs	40	(40)
Proceeds from exercise of stock options	225	303
Proceeds from exercise of common stock warrants		1
Payment on note payable		(3,335)
Proceeds from notes payable		20,667
Payment of deferred financing fees		(486)
Return of short swing profits		6
Net cash flows from financing activities	2,724	17,116
Net change in cash and cash equivalents	(26,096)	(2,817)
Cash and cash equivalents at beginning of year	83,560	70,472
Cash and cash equivalents at end of year	57,464	67,655
Cash paid for interest	$ 1,358	$ 491