CONDENSED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT (unaudited) - 9 months ended Sep. 30, 2018 - USD ($)	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit	Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017	$ 89,633,543					$ 89,634,000
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2017	9,131,999					9,131,999
Issuance of redeemable preferred stock						$ 14,890,000
Issuance of redeemable preferred stock, shares						1,842,959
Issuance of redeemable preferred stock upon conversion of promissory notes						$ 19,778,000
Issuance of redeemable preferred stock upon conversion of promissory notes, shares						2,080,209
Exercises of warrants						$ 1,212,000
Exercises of warrants, shares						144,948
Temporary equity, Accretion of redeemable preferred stock to redemption value						$ 95,000
Redeemable convertible preferred stock, ending balance at Sep. 30, 2018	$ 125,609,295					$ 125,609,000
Redeemable convertible preferred stock, ending balance, shares at Sep. 30, 2018	13,200,115					13,200,115
Beginning balance at Dec. 31, 2017	$ (97,416,000)	$ 1,000	$ (24,000)	$ 1,672,000	$ (99,065,000)
Beginning balance, shares at Dec. 31, 2017	745,788	775,755	(29,967)
Exercises of stock options	$ 53,000			53,000
Exercises of stock options, shares		19,885
Stock-based compensation	262,000			262,000
Accretion of redeemable preferred stock to redemption value	(95,000)			(95,000)
Net loss	(18,978,000)				(18,978,000)
Ending balance at Sep. 30, 2018	$ (116,174,000)	$ 1,000	$ (24,000)	$ 1,892,000	$ (118,043,000)
Ending balance, shares at Sep. 30, 2018	765,673	795,640	(29,967)