Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 55,518	$ 25,303
Prepaid expenses and other current assets	2,314	935
Total current assets	57,832	26,238
Property and equipment, net	2,418	3,751
Restricted cash	263	263
Other assets	177	129
Total assets	60,690	30,381
Current liabilities:
Current portion of long-term debt	7,461	5,576
Accounts payable	854	629
Accrued expenses	1,358	3,122
Derivative liability related to loan		494
Total current liabilities	9,673	9,821
Long-term debt, net of current portion	3,730	9,293
Total liabilities	13,403	19,114
Commitments and contingencies (Note 11)
Convertible preferred stock - 207,164,404 authorized, issued, and outstanding as of December 31, 2019. No shares authorized, issued, and outstanding as of September 30, 2020.		129,870
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value: 10,000,000 shares authorized and no shares issued and outstanding as of September 30, 2020; no shares issued and outstanding as of December 31, 2019
Common stock, $0.0001 par value: 300,000,000 shares authorized; 52,123,374 and 9,073,002 shares issued at September 30, 2020 and December 31, 2019, respectively; 51,672,326 and 7,034,047 shares outstanding at September 30, 2020 and December 31, 2019, respectively	5	1
Additional paid-in-capital	190,299	3,304
Accumulated deficit	(143,017)	(121,908)
Total stockholders' equity (deficit)	47,287	(118,603)
Total liabilities and stockholders' equity (deficit)	$ 60,690	$ 30,381