Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (9,322,000)	$ (14,883,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Impairment of commitment asset	1,521,000
Stock-based compensation expense	1,128,000	999,000
Depreciation, amortization and accretion	538,000	367,000
Amortization of right-of-use assets	282,000	395,000
Gain on foreign currency translation	(1,796,000)	(1,935,000)
Interest expense on promissory notes	1,257,000	1,134,000
Write-off of inventory	496,000	0
Other, net	19,000	104,000
Changes in operating assets and liabilities:
Accounts receivable, net	(1,661,000)	258,000
Inventory	428,000	(123,000)
Prepaid expenses and other current assets	988,000	164,000
Other assets	40,000	(340,000)
Accounts payable	1,942,000	1,599,000
Accrued expenses and other current liabilities	1,880,000	2,336,000
Deferred revenue	(8,235,000)	686,000
Operating lease liabilities	(724,000)	(395,000)
Recognized loss on purchase commitments		(1,963,000)
Net cash used in operating activities	(11,219,000)	(11,597,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(150,000)	(269,000)
Purchase of treasury bills		(24,764,000)
Proceeds from sale of treasury bills	20,000,000
Net cash provided by (used in) investing activities	19,850,000	(25,033,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Exercise of stock options	8,000
Payment of employment taxes related to vested restricted stock units	(325,000)
Other		3,000
Net cash provided by financing activities	331,000	3,000
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH	8,962,000	(36,627,000)
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD	30,222,000	71,684,000
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD	39,184,000	35,057,000
SUPPLEMENTAL CASH FLOWS DISCLOSURES:
Interest paid in cash, net of amounts capitalized	885,000
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Common stock issuance to settle employee stock purchase plan liability	318,000	317,000
Payment of interest on senior convertible notes through common stock issuance	144,000	534,000
Non-cash construction in progress and property and equipment	32,000	246,000
Addition of right-of-use assets upon adoption of new lease guidance		$ 5,192,000
At The Market Issuance
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from at-the-market offering	668,000
Issuance costs associated with at-the-market offering	$ 20,000