Capital Stock - Textual (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Apr. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 28, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Stock options exercised (shares)		63,509	361,145
Weighted average exercise price of stock options exercised (usd per share)		$ 2.76	$ 2.60
Proceeds from exercises of stock options		$ 175	$ 939
Shares issued (shares)	6,300,000
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001			$ 0.0001
Share price (usd per share)	$ 4.00
Net proceeds from public offering	$ 23,200
Underwriting discounts, commissions and other offering expenses	$ 600
Warrants Issued on September 28, 2017
Class of Stock [Line Items]
Warrant outstanding (in shares)		0		72,727
Warrant price per share (in dollars per share)				$ 8.25