Consolidated balance sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents (Note 3)	$ 76,928	$ 52,032
Short-term investments (Note 13)		56,053
Receivables, prepayments and deposits	237	740
Total current assets	77,165	108,825
Property and equipment, net (Note 4)	400	905
Long-term prepayments and deposits	53	599
Total assets	77,618	110,329
Current liabilities
Accounts payable and other liabilities (Note 5)	4,627	10,956
Total current liabilities	4,627	10,956
Other liabilities (Note 6)	319	486
Total liabilities	4,946	11,442
Commitments and contingencies (Note 15)
Share capital:
Common stock	0	0
Preferred stock
Additional paid-in capital	302,759	297,459
Accumulated deficit	(230,087)	(198,502)
Accumulated other comprehensive loss		(70)
Total stockholders' equity	72,672	98,887
Total liabilities and stockholders' equity	$ 77,618	$ 110,329