Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended
	Jan. 24, 2018	Jan. 04, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Shareholders' Equity Disclosure [Abstract]
Common stock, shares outstanding (in shares)		26,281,396	39,506,527		6,795,627
Gross proceeds, offering amount			$ 78,518	$ 0
Underwriting expenses			$ 5,300
Common Stock [Member]
Shareholders' Equity Disclosure [Abstract]
Conversion of convertible preferred shares into common shares (in shares)		(19,475,788)	19,475,788
Number of shares sold (in shares)			6,325,000
Underwriting Agreement [Member]
Shareholders' Equity Disclosure [Abstract]
Number of shares sold (in shares)	6,325,000
Options granted (in shares)	825,000
Public offering price (in dollars per share)	$ 13.25
Gross proceeds, offering amount	$ 83,806
Underwriting expenses	5,288
Net proceeds, offering amount	$ 78,518