The Company and Basis of Presentation (Private Placement Offering) (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Feb. 12, 2018	Mar. 15, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Private Placement Offering
Issuance of stock (in shares)	3,592,858
Gross proceeds			$ 25,150		$ 30,278
Exercise price of warrant			$ 10.40
Term of warrants			5 years
Private placement
Private Placement Offering
Issuance of stock (in shares)		1,324,256
Price per issue and sold units		$ 9.47
Gross proceeds		$ 12,500		$ 8,979
Number of shares per unit		1
Number of warrants per unit		0.75
Exercise price of warrant		$ 10.40
Term of warrants		5 years