Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (5,533)	$ (12,381)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	135	305
Amortization of premium/discount on investments	(41)	(132)
Non-cash interest expense	44	35
Stock-based compensation expense	986	754
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(623)	303
Right-of-use asset	147	0
Accounts payable and accrued liabilities	(4,005)	106
Deferred revenue	(1,091)	0
Lease liabilities	287	(213)
Net cash used in operating activities	(9,694)	(11,223)
Investing activities
Purchases of property and equipment	(56)	(121)
Purchase of short-term investments	(4,914)	(13,296)
Maturities of short-term investments	18,100	31,125
Proceeds from the sale of short-term investments	0	1,391
Net cash provided by investing activities	13,130	19,099
Financing activities
Proceeds from borrowings, net of issuance costs	5,000	0
Proceeds from sale of common stock, net of offering costs	0	23,618
Repayment of debt	0	(500)
Net cash provided by financing activities	5,000	23,118
Effect of exchange rate on cash, cash equivalents and restricted cash	(113)	(14)
Net increase in cash and cash equivalents and restricted cash	8,323	30,980
Cash and cash equivalents and restricted cash, beginning of period	16,509	10,843
Cash and cash equivalents and restricted cash, end of period	24,832	41,823
Supplemental Information
Discount in connection with issuance of debt	335	0
Cash paid for interest	73	35
Recognition of right-of-use asset	$ 0	$ 883