Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 38,046	$ 148,627
Marketable securities	450,492	42,900
Prepaid expenses and other current assets	767	485
Total current assets	489,305	192,012
Property and equipment, net	244	301
Total assets	489,549	192,313
Current liabilities:
Accounts payable	1,031	1,929
Accrued expenses	5,611	8,125
Total current liabilities	6,642	10,054
Total liabilities	6,642	10,054
Stockholders' equity:
Preferred stock, par value $0.0001 per share authorized: 5,000,000 shares at June 30, 2018 and December 31, 2017; 1,969,797 shares issued and outstanding at June 30, 2018 and December 31, 2017
Common stock, par value $0.0001 per share authorized: 200,000,000 at June 30, 2018 and December 31, 2017; 15,393,309 and 14,227,634 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	2	1
Additional paid-in-capital	610,845	288,750
Accumulated other comprehensive loss	(143)	(31)
Accumulated deficit	(127,797)	(106,461)
Total stockholders' equity	482,907	182,259
Total liabilities and stockholders' equity	$ 489,549	$ 192,313

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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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).