CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE AND CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIENCY) - USD ($) $ in Thousands	Common Stock Subscription Agreement	Common Stock Private placement	Common Stock	Additional Paid-in Capital Subscription Agreement	Additional Paid-in Capital Private placement	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Subscription Agreement	Private placement	Series A Redeemable Convertible Preferred Stock	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Total
Balance at the beginning of the period (in shares) at Dec. 31, 2015											9,000,000	21,500,000	11,781,984
Balance at the end of the period (in shares) at Dec. 31, 2016											9,000,000	21,500,000	11,781,984
Balance at the beginning of the period at Dec. 31, 2015											$ 11,080	$ 26,512	$ 28,289
Increase (Decrease) in Redeemable Convertible Preferred Stock
Accretion to redemption value											720	1,677	2,253
Balance at the end of the period at Dec. 31, 2016											$ 11,800	$ 28,189	$ 30,542
Balance at the beginning of the period at Dec. 31, 2015						$ 100	$ (1)	$ (70,388)						$ (70,289)
Increase (Decrease) in Stockholders' Deficit
Accretion to redemption value								(4,650)						(4,650)
Foreign currency translation adjustment							295							295
Stock-based compensation						45								45
Net loss								(25,632)						(25,632)
Balance at the end of the period at Dec. 31, 2016						145	294	(100,670)						$ (100,231)
Increase (Decrease) in Shares Outstanding
Conversion of notes payable - related party and accrued interest into stock (in shares)			1,950,768
Conversion of convertible preferred stock to common stock (in shares)			3,174,523								(9,000,000)	(21,500,000)	(11,781,984)
Issuance of stock (in shares)	1,010,225	2,958,094
Issuance of common stock in connection with merger with Macrocure (in shares)			3,256,898
Issuance of common stock upon exercise of stock options (in shares)			3,506											3,506
Balance at the end of the period (in shares) at Dec. 31, 2017			12,354,014
Increase (Decrease) in Redeemable Convertible Preferred Stock
Accretion to redemption value											$ 37	$ 90	$ 117
Conversion of convertible preferred stock to common stock											$ (11,837)	$ (28,279)	$ (30,659)
Increase (Decrease) in Stockholders' Deficit
Accretion to redemption value						(244)								$ (244)
Conversion of notes payable - related party and accrued interest into common stock			$ 2			31,143								31,145
Conversion of convertible preferred stock to common stock			3			70,772								70,775
Issuance of common stock, net of issuance costs	$ 1	$ 3		$ 8,981	$ 5,426				$ 8,982	$ 5,429
Issuance of common stock in connection with merger with Macrocure, net of offering costs of $1,331			3			19,927								19,930
Issuance of common stock upon exercise of stock options						20								20
Foreign currency translation adjustment							(562)							(562)
Stock-based compensation						5,600								5,600
Net loss								(29,727)						(29,727)
Balance at the end of the period at Dec. 31, 2017			$ 12			$ 141,770	$ (268)	$ (130,397)						$ 11,117