Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 332,254	$ 250,456
Receivable from collaborative partners	642	0
Short-term investments	58,597	143,197
Prepaid expenses and other current assets	6,508	2,908
Restricted cash	60	0
Total current assets	398,061	396,561
Property and equipment, net	2,488	1,783
Operating lease right-of-use assets	20,278	344
Long-term investments	5,484	17,546
Other long-term assets	258	258
Restricted cash	0	60
Total assets	426,569	416,552
Current liabilities:
Accounts payable	4,103	4,217
Accrued expenses	15,958	15,262
Current portion of operating lease liability	555	342
Total current liabilities	20,616	19,821
Operating lease liability, net of current portion	20,222	0
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at June 30, 2021 and December 31, 2020, respectively	0	0
Common stock, $0.001 par value, 500,000 shares authorized, 27,433 shares and 27,356 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	27	27
Additional paid in capital	668,429	660,665
Accumulated other comprehensive loss	(176)	(4)
Accumulated deficit	(282,549)	(263,957)
Total stockholders’ equity	385,731	396,731
Total liabilities and stockholders’ equity	$ 426,569	$ 416,552

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).