Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (15,074,000)	$ (8,897,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	542,000	326,000
Amortization of intangible assets	3,000	2,000
Amortization of investment discount	37,000	47,000
Equity-based compensation	1,686,000	1,657,000
(Increase) in assets:
Accounts receivable	0	(14,000)
Prepaid expense and other	(518,000)	(104,000)
Other current assets	(1,212,000)	(647,000)
Increase (decrease) in liabilities:
Accounts payable	494,000	166,000
Accrued liabilities	906,000	501,000
Deferred revenue and income	(69,000)	0
Net cash used in operating activities	(13,205,000)	(6,963,000)
Cash flows from investing activities:
Purchases of equipment	(1,681,000)	(1,198,000)
Purchase of available-for-sale securities	(36,718,000)	(4,503,000)
Sales of available-for-sale securities	500,000	107,000
Maturity of available-for-sale securities	3,400,000	6,355,000
Net cash provided by (used in) investing activities	(34,499,000)	761,000
Cash flows from financing activities:
Exercise of warrants and options	28,000	66,000
Common stock issuance costs	(814,000)	0
Payments on capital lease obligations	(13,000)	(36,000)
Net cash provided by (used in) financing activities	(799,000)	30,000
Effect of exchange rate on cash	(49,000)	0
Decrease in cash and cash equivalents	(48,552,000)	(6,172,000)
Cash and cash equivalents, beginning of period	120,585,000	53,563,000
Cash and cash equivalents, end of period	$ 72,033,000	$ 47,391,000