Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Federal
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 31,336	$ 32,870
Research tax credits (expiring through 2025)	168	168
Alternative minimum tax credits (available without expiration)	86	70
State | Tennessee (expiring in 2030)
Operating Loss Carryforwards [Line Items]
Net operating losses	529	568
State | New Jersey (expiring in 2035)
Operating Loss Carryforwards [Line Items]
Net operating losses	1,764	822
State | Illinois (expiring in 2035)
Operating Loss Carryforwards [Line Items]
Net operating losses	222	255
Foreign
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 232	$ 10