Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 324,117	$ 240,430
Prepaid expenses and other current assets	8,321	4,750
Total current assets	332,438	245,180
Property and equipment, net	56,174	24,201
Other long-term assets	2,966	1,194
Total assets	391,578	270,575
Current liabilities:
Accounts payable	10,587	3,197
Accrued expenses	44,938	16,794
Accrued indemnification obligation	2,788	4,452
Total current liabilities	58,313	24,443
Long-term liabilities	525
Total liabilities	58,838	24,443
Preferred stock
Common stock; par value $0.0001 per share, 100,000,000 shares authorized, 31,972,377 shares issued and outstanding at September 30, 2017; 27,700,054 shares issued and outstanding at December 31, 2016	3	3
Additional paid-in capital	692,350	387,691
Accumulated deficit	(359,613)	(141,562)
Total stockholders’ equity	332,740	246,132
Total liabilities, redeemable common stock and stockholders’ equity	$ 391,578	$ 270,575

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).