Warrants - Issued April 4, 2014 Black Scholes (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair value assumptions and methodology for assets and liabilities
Number of warrants (in shares)	563,998	913,441
Warrants Issued April 4, 2014, Liability
Fair value assumptions and methodology for assets and liabilities
Number of warrants (in shares)	132,800	132,800
CDTi stock price (in dollars per share)	$ 1.65	$ 4.70
Strike price (in dollars per share)	$ 21.00	$ 21.00
Expected volatility	103.80%	94.40%
Risk-free interest rate	0.80%	1.50%
Expected life in years	3 years 3 months 18 days	3 years 9 months 18 days
Warrants Issued April 4, 2014, Liability | November 23, 2015 Offering
Fair value assumptions and methodology for assets and liabilities
Number of warrants (in shares)	29,600	29,600
CDTi stock price (in dollars per share)	$ 1.65	$ 4.70
Strike price (in dollars per share)	$ 8.50	$ 8.50
Expected volatility	91.20%	96.70%
Risk-free interest rate	0.80%	1.60%
Expected life in years	3 years 10 months 24 days	4 years 4 months 24 days