Financial Instruments (Details Textual) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Instruments (Textual) [Abstract]
Short-term investments contractual maturity period minimum										5 months
Short-term investments contractual maturity period maximum										6 months
Average short-term investments maturity period										3 months
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill impairment charges	$ 0	$ 0	$ 0	$ 0	$ 5,698	$ 0	$ 0	$ 0		$ 0	$ 5,698	$ 0
Discontinued Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill impairment charges								$ 5,700	$ 3,400			$ 3,388