Consolidated Statement of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss	$ (64,028,000)	$ (66,374,000)	$ (45,498,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,184,000	2,340,000	1,782,000
Amortization of intangible assets	12,000	11,000	10,000
Amortization of investment discount	326,000	374,000	188,000
Equity-based compensation	13,933,000	8,775,000	8,388,000
Realized gain on available-for-sale securities	0	(6,000)	0
Loss on disposal of property and equipment	240,000	23,000	0
(Increase) decrease in assets:
Accounts receivable	(1,912,000)	43,000	1,000
Inventory	(7,759,000)	0	0
Prepaid expense and other	(174,000)	1,292,000	(1,241,000)
Other current assets	(285,000)	(171,000)	(12,000)
Increase (decrease) in liabilities:
Accounts payable	1,064,000	(1,242,000)	329,000
Accrued liabilities	596,000	1,619,000	827,000
Deferred revenue and income	36,000	(92,000)	100,000
Deferred compensation	21,000	0	0
Net cash used in operating activities	(55,746,000)	(53,408,000)	(35,126,000)
Cash flows from investing activities:
Purchases of equipment	(2,966,000)	(2,409,000)	(3,656,000)
Purchase of available-for-sale securities	(82,333,000)	(74,075,000)	(12,418,000)
Sales of available-for-sale securities	11,522,000	9,716,000	141,000
Maturity of available-for-sale securities	48,049,000	17,200,000	13,258,000
Net cash used in investing activities	(25,728,000)	(49,568,000)	(2,675,000)
Cash flows from financing activities:
Exercise of warrants and options	6,606,000	1,497,000	805,000
Common stock issuance cost	0	(814,000)	0
Issuance of common stock and warrants	83,821,000	226,000	104,165,000
Recovery of related party short-swing profits	0	866,000	0
Payments on capital lease obligations	0	(13,000)	(147,000)
Net cash provided by financing activities	90,427,000	1,762,000	104,823,000
Effect of exchange rate on cash	316,000	(127,000)	0
Increase (decrease) in cash and cash equivalents	9,269,000	(101,341,000)	67,022,000
Cash and cash equivalents, beginning of period	19,244,000	120,585,000	53,563,000
Cash and cash equivalents, end of period	$ 28,513,000	$ 19,244,000	$ 120,585,000