Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (17,909)	$ (15,283)
Adjustments to reconcile net loss to net cash used in operating activities:
Inventory write-off	435	155
Depreciation and amortization	835	1,216
Provision for doubtful accounts	110	0
Licensing revenue from a related party	(5,000)	0
Stock-based compensation	1,525	566
Interest cost	760	608
Loss in joint venture	6,836	3,703
Changes in fair value of promissory note	(927)	167
Changes in operating assets and liabilities:
Accounts receivable	(245)	(429)
Inventory	(1,072)	(293)
Prepaid expenses and other current assets	(283)	(154)
Other assets	206	(42)
Accounts payable and accrued expenses	(116)	509
Deferred revenue	674	(3,000)
Accrued payroll and benefits	56	(13)
Net cash used in operating activities	(14,115)	(12,290)
Cash flows from investing activities:
Purchases of property and equipment	(58)	(203)
Investment in joint venture	(7,348)	(2,698)
Net cash used in investing activities	(7,406)	(2,901)
Cash flows from financing activities:
Proceeds from development loans	0	15,000
Proceeds from stock option exercise	32	0
Payment for repurchase of common stock	(211)	0
Loan repayment	(50)	0
Proceeds from issuance of common stock, net of $3.1 million offering cost	33,387	0
Net cash provided by financing activities	33,158	15,000
Effect of foreign exchange rate changes on cash and cash equivalents	182	(3)
Net increase (decrease) in cash and cash equivalents	11,819	(194)
Cash and cash equivalents at beginning of period	2,875	3,069
Cash and cash equivalents at end of period	14,694	2,875
Supplemental disclosures of cash flow information:
Interest expense paid	915	496
Supplemental non-cash financing activity:
Private placement offering cost	223	177
Development loan reduction related to licensing revenue	5,000	0
Conversion of preferred stock to common stock in connection with the Reverse Merger	$ 85,658	$ 0