CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 98,104	$ 225,848
Investments	78,413	0
Prepaid expenses and other current assets	3,526	3,975
Total current assets	180,043	229,823
Operating lease, right-of-use-asset	33,847	35,095
Property, plant and equipment, net	51,660	51,530
Restricted cash	1,573	1,573
Total assets	267,123	318,021
Current liabilities:
Accounts payable	12,084	11,572
Accrued expenses and other current liabilities	7,752	14,072
Operating lease liabilities	9,082	9,015
Total current liabilities	28,918	34,659
Long-term debt, net of discount	76,377	76,154
Other long-term liabilities	101	135
Operating lease liabilities, net of current portion	27,078	28,291
Total liabilities	132,474	139,239
Commitments and contingencies (see Note 9)
Stockholders' equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized at March 31, 2022 and December 31, 2021; no shares issued or outstanding at March 31, 2022 and December 31, 2021
Common stock, $0.001 par value; 150,000,000 shares authorized at March 31, 2022 and December 31, 2021; 90,186,626 and 90,063,770 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	90	90
Additional paid-in capital	864,046	855,710
Accumulated other comprehensive income	(57)
Accumulated deficit	(729,430)	(677,018)
Total stockholders' equity	134,649	178,782
Total liabilities and stockholders' equity	$ 267,123	$ 318,021