CONSOLIDATED STATEMENT OF CHANGESIN SHAREHOLDERS’ EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Exercise of stock options, shares tendered in payment of exercise price (in shares)	19,294	19,658	846,789
Shares paid for tax withholding for share-based compensation	522,190	218,587	901,691
Shares surrendered for tax withholding			$ 2,038
Preferred Stock
Underwriting discount and expenses	$ 273	$ 958	$ 723
Option
Exercise of stock options, shares tendered in payment of exercise price (in shares)	1,194,324	1,715,019	1,129,195
Warrant
Exercise of stock options, shares tendered in payment of exercise price (in shares)			846,789