Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (2,270)	$ (5,901)	$ (6,457)	$ (12,271)
Adjustments to reconcile net loss to net cash used in operating activities:
Inventory write-off	0		162	0
Depreciation and amortization			438	615
Licensing revenue from a related party			(5,000)	0
Stock-based compensation			236	276
Interest cost			378	376
Loss in joint venture	1,856	1,100	3,275	2,227
Changes in fair value of promissory note	1,658	51	(663)	84
Changes in operating assets and liabilities:
Accounts receivable			(60)	(10)
Inventory			(514)	(277)
Prepaid expenses and other current assets			(1,050)	4
Other assets			80	(61)
Accounts payable and accrued expenses			(719)	(473)
Deferred revenue			193	3,000
Accrued payroll and benefits			189	44
Net cash used in operating activities			(9,512)	(6,466)
Cash flows from investing activities:
Purchases of property and equipment			(22)	(116)
Investment in joint venture			(3,427)	(1,103)
Net cash used in investing activities			(3,449)	(1,219)
Cash flows from financing activities:
Proceeds from development loans			0	9,000
Proceeds from stock option exercise			18	0
Payment for repurchase of common stock			(211)	0
Loan repayment			(50)	0
Proceeds from issuance of common stock, net of offering cost			19,741	0
Net cash provided by financing activities			19,498	9,000
Effect of foreign exchange rate changes on cash and cash equivalents			(30)	14
Net increase in cash and cash equivalents			6,507	1,329
Cash and cash equivalents at beginning of period			2,875	3,069	$ 3,069
Cash and cash equivalents at end of period	$ 9,382	$ 4,398	9,382	4,398	$ 2,875
Supplemental disclosures of cash flow information:
Interest expense paid			0	496
Supplemental non-cash financing activity:
Development loan reduction related to licensing revenue			$ 5	$ 0