Condensed consolidated balance sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents (Note 3)	$ 66,610	$ 52,032
Short-term investments (Note 8)	26,050	56,053
Receivables, prepayments and deposits	1,563	740
Total current assets	94,223	108,825
Property and equipment, net	849	905
Long-term prepayments and deposits	551	599
Total assets	95,623	110,329
Current liabilities
Accounts payable and other liabilities	9,355	10,956
Total current liabilities	9,355	10,956
Other liabilities (Note 4)	443	486
Total liabilities	9,798	11,442
Share capital: (Note 5)
Common stock	0	0
Additional paid-in capital	298,974	297,459
Accumulated deficit	(213,125)	(198,502)
Accumulated other comprehensive loss	(24)	(70)
Total stockholders' equity	85,825	98,887
Total liabilities and stockholders' equity	$ 95,623	$ 110,329