CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 106,336	$ 46,928
Short-term investments	97,870	186,452
Prepaid expenses and other current assets	8,849	8,247
Total current assets	213,055	241,627
Property and equipment, net	5,804	6,398
Operating lease right-of-use assets	1,629	1,927
Restricted cash	210	210
Deferred tax assets	5,410	4,372
Total assets	226,108	254,534
Current liabilities:
Accounts payable	4,274	5,693
Accrued expenses	13,379	20,415
Operating lease liabilities	1,689	1,697
Other current liabilities		25
Total current liabilities	19,342	27,830
Non-current liabilities:
Non-current operating lease liabilities	551	955
Other long-term liabilities	381	326
Total liabilities	20,274	29,111
Commitments and contingencies (Note 12)
Shareholders’ equity:
Additional paid-in capital	588,090	581,467
Accumulated other comprehensive income	240	33
Accumulated deficit	(382,511)	(356,092)
Total shareholders’ equity	205,834	225,423
Total liabilities and shareholders’ equity	226,108	254,534
Class A common shares
Shareholders’ equity:
Common stock value	6	6
Class B common shares
Shareholders’ equity:
Common stock value	1	1
Class A1 common shares
Shareholders’ equity:
Common stock value	4	4
Class B1 common shares
Shareholders’ equity:
Common stock value	$ 4	$ 4