Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents		$ 153,192	$ 180,002
Short term investments		94,809	110,704
Prepaid expenses and other current assets		15,249	12,922
Total current assets		263,250	303,628
Property and equipment, net		19,066	17,938
Operating lease assets		26,246	18,208
Restricted cash		8,185	8,000
Restricted investments		1,401	1,401
Long term investments		0	495
Other non-current assets		1,741	5,189
Total assets		319,889	354,859
Current liabilities:
Accounts payable		6,791	13,735
Accrued expenses and other current liabilities	[1]	48,278	45,094
Operating lease liabilities		6,849	6,610
Deferred revenue - related party		20,441	16,819
Total current liabilities		82,359	82,258
Long term portion of note payable, net of discount		50,437	24,643
Operating lease liabilities, net of current portion		20,346	17,958
Deferred revenue, net of current portion - related party		81,883	86,998
Other long-term liabilities	[2]	3,908	11,495
Total liabilities		238,933	223,352
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized at March 31, 2022 and December 31, 2021; no shares issued and outstanding at March 31, 2022 and December 31, 2021		0	0
Common stock, $0.001 par value; 200,000,000 shares authorized at March 31, 2022 and December 31, 2021; 91,841,974 and 91,459,239 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively		92	92
Additional paid-in capital		752,057	745,829
Accumulated other comprehensive income (loss)		(215)	(60)
Accumulated deficit		(670,978)	(614,354)
Total stockholders’ equity		80,956	131,507
Total liabilities and stockholders’ equity		$ 319,889	$ 354,859

[1] Includes related party amounts of $29,809 and $21,098 at March 31, 2022 and December 31, 2021, respectively (see Note 11)

[2] Includes related party amounts of $2,981 and $10,585 at March 31, 2022 and December 31, 2021, respectively (see Note 11)