CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 24,720	$ 24,918
Marketable securities	73,686	86,592
Prepaid expenses and other current assets	4,200	4,088
Total current assets	102,606	115,598
Property and equipment, net	2,929	2,982
Other assets	389	389
Total assets	105,924	118,969
Current liabilities:
Accounts payable	3,131	2,383
Accrued expenses	4,539	4,935
Deferred revenue, current	3,135	4,096
Other current liabilities	338	328
Total current liabilities	11,143	11,742
Deferred rent, net of current portion	2,157	2,185
Deferred revenue, non-current	983	863
Total liabilities	14,283	14,790
Commitments
Stockholders' equity:
Preferred stock
Common stock	2	2
Additional paid-in capital	323,184	319,196
Accumulated other comprehensive loss	(189)	(177)
Accumulated deficit	(231,356)	(214,842)
Total stockholders' equity	91,641	104,179
Total liabilities and stockholders' equity	$ 105,924	$ 118,969

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).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
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).