Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (4,187)	$ (6,370)
Adjustments to reconcile net loss to net cash used in operating activities:
Inventory write-off	169	0
Depreciation and amortization	236	304
Stock-based compensation	132	139
Interest cost	189	187
Loss in joint venture	1,419	1,127
Changes in fair value of promissory note	(2,321)	33
Changes in operating assets and liabilities:
Accounts receivable	(668)	(407)
Inventory	(264)	70
Prepaid expenses and other current assets	(603)	164
Other assets	9	1
Accounts payable and accrued expenses	(179)	(449)
Accrued payroll and benefits	(83)	(150)
Net cash used in operating activities	(6,151)	(5,351)
Cash flows from investing activities:
Investment in joint venture	(1,548)	(189)
Net cash used in investing activities	(1,548)	(189)
Cash flows from financing activities:
Proceeds from development loans	0	5,000
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	5,000
Effect of foreign exchange rate changes on cash and cash equivalents	(26)	(22)
Net increase (decrease) in cash and cash equivalents	11,773	(562)
Cash and cash equivalents at beginning of period	2,875	3,069	$ 3,069
Cash and cash equivalents at end of period	14,648	2,507	$ 2,875
Supplemental disclosures of cash flow information:
Interest expense paid	$ 0	$ 346