Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 89,893	$ 37,403
Restricted cash	279	0
Accounts receivable	5,000	0
Prepaid expenses and other current assets	1,495	4,673
Total current assets	96,667	42,076
Property and equipment, net	1,222	2,127
Right-of-use asset, net	301
Long-term restricted cash	1,379	279
Total assets	99,569	44,482
Current liabilities:
Accounts payable	500	1,100
Accrued expenses	13,492	11,700
Loan payable	18,905	21,385
Lease liability	372
Deferred revenue	1,674	959
Total current liabilities	34,943	35,144
Non‑current liabilities:
Deferred revenue	14,680	13,818
Warrant liabilities	41,549	0
Other long‑term liabilities	0	938
Total liabilities	91,172	49,900
Commitments and contingencies (Note 17)
Stockholders’ equity (deficit):
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	0	0
Common stock, $0.0001 par value; 200,000,000 shares authorized; 86,325,547 and 22,471,776 shares issued and outstanding as of December 31, 2019 and December 31, 2018, respectively	9	3
Additional paid-in capital	348,664	279,539
Accumulated deficit	(335,753)	(280,403)
Accumulated other comprehensive loss	(4,523)	(4,557)
Total stockholders’ equity (deficit)	8,397	(5,418)
Total liabilities and stockholders’ equity (deficit)	$ 99,569	$ 44,482