Consolidated Balance Sheets (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value
Common stock, shares authorized	Unlimited	Unlimited
Common stock, shares issued	93,254,185	89,478,032
Common stock, shares outstanding	93,254,185	89,478,032