CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (unaudited) - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Total revenue	$ 0	$ 0	$ 0	$ 425,000
Operating expenses:
Research and development	2,779,000	2,909,000	6,034,000	5,783,000
General and administrative	2,351,000	2,241,000	4,303,000	4,454,000
Loss from change in fair value of contingent consideration	3,900,000	2,200,000	2,700,000	3,700,000
Total operating expenses	9,030,000	7,350,000	13,037,000	13,937,000
Loss from operations	(9,030,000)	(7,350,000)	(13,037,000)	(13,512,000)
Other income:
Other income, net	72,000	34,000	116,000	135,000
Total other income, net	72,000	34,000	116,000	135,000
Net loss and comprehensive loss	$ (8,958,000)	$ (7,316,000)	$ (12,921,000)	$ (13,377,000)
Net loss per share — basic and diluted (in dollars per share)	$ (0.16)	$ (0.30)	$ (0.28)	$ (0.54)
Weighted-average number of common shares used in net loss per share- basic and diluted (in shares)	56,421	24,685	46,105	24,648
License revenue
Revenue:
License revenue	$ 0	$ 0	$ 0	$ 425,000