CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, no par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	63,400,348	61,966,188
Common stock, shares outstanding	63,400,348	61,966,188
Series A convertible preferred stock
Preferred stock, shares authorized	25,000	25,000
Preferred stock, shares outstanding	0	0