CONSOLIDATED STATEMENT OF CONVERTIBLE PREFERRED SHARES AND SHAREHOLDERS' EQUITY (DEFICIT) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Series A Convertible Preferred Shares	Common Shares	Additional Paid-in Capital	Accumulated Deficit	Total
Balance, beginning of period at Dec. 31, 2016	$ 43,270				$ 43,270
Balance, beginning of period (in shares) at Dec. 31, 2016	4,948,369
Increase (decrease) in temporary equity
Issuance of Series A preferred shares, net of offering costs of $1334	$ 38,666
Issuance of Series A preferred shares, net of offering costs of $1334 (in shares)	4,305,182
Issuance of Series A preferred shares as payment of offering costs (in shares)	105,009
Conversion of convertible preferred shares to common shares	$ (81,936)
Conversion of convertible preferred shares to common shares (in shares)	(9,358,560)
Balances at Dec. 31, 2016		$ 19,944	$ 10,479	$ (75,456)	(45,033)
Balances (in shares) at Dec. 31, 2016		13,088,500
Increase (Decrease) in Stockholders' Equity
Beneficial conversion feature on Series A preferred shares	$ (12,006)		12,006		12,006
Accretion of beneficial conversion feature on Series A preferred shares	$ 12,006		(12,006)		(12,006)
Issuance of common shares as payment of equity investment		$ 352			352
Issuance of common shares as payment for equity investment (Note 5) (in shares)		32,500
Conversion of convertible preferred shares to common shares		$ 81,936			81,936
Conversion of convertible preferred shares to common shares (in shares)		9,358,560
Issuance of common shares in settlement of contingent equity liability		$ 32,020			32,020
Issuance of common shares in settlement of contingent equity liability (in shares)		1,883,523
Issuance of common shares upon completion of initial public offering, net of offering costs		$ 176,128			176,128
Issuance of common shares upon completion of initial public offering, net of offering costs (in shares)		11,385,000
Issuance of common share warrant as consideration for services			93		93
Exercise of stock options		$ 255	(255)
Exercise of stock options (in shares)		182,615
Share-based compensation expense			10,805		10,805
Net loss				(100,108)	(100,108)
Balances at Sep. 30, 2017		$ 310,635	$ 21,122	$ (175,564)	$ 156,193
Balances (in shares) at Sep. 30, 2017		35,930,698