Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net loss	$ (18,733)	$ (8,193)
Depreciation	86	85
Accretion of debt discount	99	162
Amortization of intangible assets	243	242
Stock-based compensation expense	4,111	3,507
Changes in assets and liabilities:
Accounts receivable	356	109
Inventories	(2,263)	(722)
Prepaid expenses and other assets	118	177
Accounts payable and accrued expenses	(438)	127
Deferred revenue	(235)	(499)
Net cash flows from operating activities	(16,656)	(5,005)
Investing activities:
Purchase of equipment	(236)	(144)
Net cash flows from investing activities	(236)	(144)
Financing activities:
Equity financing costs	40
Proceeds from exercise of stock options	225	131
Proceeds from issuance of common stock	2,460
Payment on note payable		(2,001)
Return of short swing profits		6
Net cash flows from financing activities	2,725	(1,864)
Net change in cash and cash equivalents	(14,167)	(7,013)
Cash and cash equivalents at beginning of year	83,560	70,472
Cash and cash equivalents at end of year	69,393	63,459
Cash paid for interest	$ 679	$ 269