Marketable Securities Maturity Schedule (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 22,659	$ 22,618
Available-for-sale Securities	22,659	22,619
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	1
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Mutual Funds, Money Market [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	17,061	13,244
Available-for-sale Securities	17,061	13,244
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		1,002
Available-for-sale Securities		1,002
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		2,283
Available-for-sale Securities		2,284
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		1
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		0
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	5,598	6,089
Available-for-sale Securities	5,598	6,089
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	4,566	5,515
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	4,566	5,516
Available-for-sale Securities, Debt Maturities, Year Two, Amortized Cost Basis	1,032	3,859
Available-for-sale Securities, Debt Maturities, Year Two, Fair Value	1,032	3,859
Available-for-sale Debt Securities, Amortized Cost Basis	5,598	9,374
Available-for-sale Securities	$ 5,598	$ 9,375