Consolidated Statement of Shareholders' Equity (Unaudited) - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Preferred Stock [Member] Series A Convertible Preferred Shares [Member]	Preferred Stock [Member] Series B Convertible Preferred Shares [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Beginning Balance at Dec. 31, 2017	$ 16,060	$ 25,406	$ 68	$ 5,340	$ (31,355)	$ 0	$ 15,519
Beginning Balance (in shares) at Dec. 31, 2017	128,738	126,909	6,795,627
Conversion of convertible preferred shares into common shares	$ (16,060)	$ (25,406)	$ 194	41,272	0	0	0
Conversion of convertible preferred shares into common shares (in shares)	(128,738)	(126,909)	19,475,788
Exchange of common shares in connection with the Merger	$ 0	$ 0	$ 68	85,992	0	0	86,060
Exchange of common shares in connection with the Merger (in shares)	0	0	6,805,608
Issuance of common stock, net of issuance costs of $5.3 million	$ 0	$ 0	$ 63	78,455	0	0	78,518
Issuance of common stock, net of issuance costs of $5.3 million (in shares)	0	0	6,325,000
Issuance of common stock pursuant to settlement of restricted stock units	$ 0	$ 0	$ 1	(1)	0	0	0
Issuance of common stock pursuant to settlement of restricted stock units (in shares)	0	0	42,968
Issuance of common stock pursuant to exercise of stock options	$ 0	$ 0	$ 1	(1)	0	0	0
Issuance of common stock pursuant to exercise of stock options (in shares)	0	0	61,536
Unrealized loss on investments	$ 0	$ 0	$ 0	0	0	(79)	(79)
Share-based compensation	0	0	0	8,168	0	0	8,168
Net loss	0	0	0	0	(31,110)	0	(31,110)
Ending Balance at Jun. 30, 2018	$ 0	$ 0	$ 395	$ 219,225	$ (62,465)	$ (79)	$ 157,076
Ending Balance (in shares) at Jun. 30, 2018	0	0	39,506,527