Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 21,661	$ 51,058
Short-term investments	111,933	85,095
Receivables from collaborations	1,712	1,997
Prepaid expenses and other current assets	1,492	2,102
Total current assets	136,798	140,252
Other assets	361	569
Restricted cash	440	440
Property and equipment, net	1,106	1,464
Operating lease right-of-use asset	7,614
Total assets	146,319	142,725
Current liabilities:
Accounts payable	713	1,247
Accrued and other liabilities	17,792	13,634
Total current liabilities	18,505	14,881
Noncurrent operating lease liability	7,155
Deferred rent		1,130
Total liabilities	25,660	16,011
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.0001 par value, 200,000 shares authorized as of September 30, 2019, and December 31, 2018; 53,775 and 38,834 shares issued and outstanding as of September 30, 2019, and December 31, 2018, respectively	5	4
Additional paid-in capital	384,962	322,993
Accumulated deficit	(264,373)	(196,170)
Accumulated other comprehensive income (loss)	65	(113)
Total stockholders’ equity	120,659	126,714
Total liabilities and stockholders’ equity	$ 146,319	$ 142,725