CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 49,436	$ 67,727
Short-term investments	2,481	4,998
Prepaid expenses and other current assets	2,276	1,215
Total current assets	54,193	73,940
Property and equipment, net	2,381	1,294
Other assets	2,391
Total assets	58,965	75,234
Current liabilities:
Accounts payable	4,973	2,472
Accrued expenses	4,231	4,437
Total current liabilities	9,204	6,909
Other long-term liabilities	3,176
Total liabilities	12,380	6,909
Stockholders' equity:
Preferred stock, $0.001 par value; 25,000,000 shares authorized, no shares issued and outstanding
Common stock, $0.001 par value; 100,000,000 shares authorized, 52,583,856 issued and 52,554,625 outstanding at June 30, 2019 and 52,548,244 issued and 52,519,013 outstanding at December 31, 2018	53	53
Additional paid-in capital	252,891	249,727
Treasury stock at cost, 29,231 shares at June 30, 2019 and December 31, 2018
Accumulated other comprehensive loss		(2)
Accumulated deficit	(206,359)	(181,453)
Total stockholders’ equity	46,585	68,325
Total liabilities and stockholders’ equity	$ 58,965	$ 75,234