Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 22,155	$ 48,606
Marketable securities	42,781
Restricted bank deposit	40	45
Prepaid expenses and other current assets	1,878	1,690
Total current assets	66,854	50,341
Property and equipment, net	220	248
Operating lease right-of-use asset	870
Other long-term assets	113	129
Total assets	68,057	50,718
Current liabilities:
Accounts payable	1,687	747
Accrued expenses	5,145	6,938
Current portion of long-term debt	3,488
Advances from collaboration partners	403
Current portion of operating lease liability	461
Taxes payable	43	122
Total current liabilities	11,227	7,807
Long-term debt	11,193
Operating lease liability	409
Stockholders’ equity:
Preferred stock, $0.01 par value per share, 5,000,000 shares authorized, no shares issued and outstanding at September 30, 2019 and December 31, 2018
Common stock, $0.01 par value per share, 500,000,000 shares authorized, 40,117,186 and 35,951,537 shares issued and 39,977,654 and 35,860,114 shares outstanding as of September 30, 2019 and December 31, 2018, respectively	404	360
Common stock in treasury, at cost, 139,532 and 91,423 shares at September 30, 2019 and December 31, 2018, respectively	(1,585)	(1,129)
Additional paid-in capital	171,783	129,825
Accumulated other comprehensive income	12
Accumulated deficit	(125,386)	(86,145)
Total stockholders’ equity	45,228	42,911
Total liabilities and stockholders' equity	$ 68,057	$ 50,718