Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net loss	$ (22,168)	$ (10,122)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	536	191
Amortization of intangible assets	56	58
Amortization of investment discount	229
Stock-based compensation	7,334	2,612
Impairment of intangibles		9
(Increase) decrease in assets:
Accounts receivable	(65)	658
Prepaid expense and other	(547)	(99)
Increase (decrease) in liabilities:
Accounts payable	528	(293)
Accrued liabilities	125	(549)
Deferred revenue and income	(22)	533
Net cash used in operating activities	(13,994)	(7,002)
Cash flows from investing activities:
Purchases of equipment	(1,357)	(1,090)
Purchase of available-for-sale securities	(6,614)	(10,949)
Sales of available-for sale securities	246
Maturity of available-for-sale securities	4,007
Net cash used in investing activities	(3,718)	(12,039)
Cash flows from financing activities:
Issuance of common stock and warrants	44,875	19,911
Exercise of warrants and options	730	20,514
Payments on capital lease obligations	(71)
Net cash provided by financing activities	45,534	40,425
Increase in cash and cash equivalents	27,822	21,384
Cash and cash equivalents, beginning of period	30,029	12,069
Cash and cash equivalents, end of period	$ 57,851	$ 33,453