Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,365	$ 21,084
Restricted cash - current	10	10
Available-for-sale securities - current	54,127	56,515
Research and development tax incentive receivable	2,881	2,241
Prepaid expenses and other current assets	1,743	3,394
Total current assets	69,126	83,244
Property and equipment, net	903	562
Restricted cash - noncurrent	450	0
Available-for-sale securities - noncurrent	0	10,150
Other assets	0	34
Total assets	70,479	93,990
Current liabilities:
Accounts payable	2,639	1,163
Accrued expenses and other payables	6,727	5,272
Total current liabilities	9,366	6,435
Deferred rent	83	0
Total liabilities	9,449	6,435
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.00001 par value, 10,000,000 shares authorized; and no shares issued and outstanding as of June 30, 2017 and December 31, 2016	0	0
Common stock, $0.00001 par value, 90,000,000 shares authorized; 16,899,261 and 16,722,280 shares issued and outstanding as of June 30, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	154,700	152,393
Accumulated other comprehensive gain (loss)	3	(245)
Accumulated deficit	(93,673)	(64,593)
Total stockholders’ equity	61,030	87,555
Total liabilities and stockholders’ equity	$ 70,479	$ 93,990