Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 106,260	$ 161,160
Marketable securities	105,328	138,343
Prepaid expenses	31,798	25,628
Receivables and other current assets	11,531	11,389
Total current assets	254,917	336,520
Marketable securities	55,049	97,114
Property, plant and equipment, net	11,234	9,706
Goodwill	5,646	5,646
Operating lease right-of-use assets	111,897	91,532
Restricted cash and other non-current assets	52,328	53,277
Total assets	491,071	593,795
Current liabilities:
Accounts payable	28,350	25,883
Accrued expenses and other current liabilities	89,032	103,958
Operating lease liability, current portion	25,510	23,152
Total current liabilities	142,892	152,993
Operating lease liability, net of current portion	84,828	66,432
Other non-current liabilities	92	93
Total liabilities	227,812	219,518
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at March 31, 2022 and December 31, 2021	0	0
Common stock, $0.01 par value, 125,000 shares authorized; 71,438 and 71,115 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	714	711
Additional paid-in capital	4,109,081	4,096,402
Accumulated other comprehensive loss	(4,459)	(2,911)
Accumulated deficit	(3,842,077)	(3,719,925)
Total stockholders’ equity	263,259	374,277
Total liabilities and stockholders’ equity	$ 491,071	$ 593,795