Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash	$ 243,312	$ 210,643
Restricted cash	786	787
Prepaid expenses and other assets, current	36,844	37,826
Total current assets	280,942	249,256
Non-current assets:
Property and equipment, net	29,800	28,164
Right of use assets, net	23,713	23,409
Long-term deposits	1,933	2,040
Prepaid expenses and other assets, non-current	652	0
Deferred tax asset	410	410
Intangible assets, net	214	254
Assets	337,664	303,533
Current liabilities:
Accounts payable	1,057	1,075
Accrued expenses and other liabilities	22,471	21,398
Lease liabilities	2,523	2,511
Total current liabilities	26,051	24,984
Non-current liabilities:
Lease liabilities	24,135	23,710
Total liabilities	50,186	48,694
Shareholders' equity:
Additional paid-in capital	580,772	500,560
Accumulated other comprehensive loss	(26,392)	(8,691)
Accumulated deficit	(267,023)	(237,150)
Total shareholders' equity	287,478	254,839
Total liabilities and shareholders' equity	337,664	303,533
Ordinary shares
Shareholders' equity:
Share value	3	2
Deferred shares
Shareholders' equity:
Share value	0	0
Deferred B Shares
Shareholders' equity:
Share value	118	118
Deferred C Shares
Shareholders' equity:
Share value	$ 0	$ 0

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).