Warrants - Issued July 3, 2013 Monte Carlo (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 July 3, 2013, Liability
Fair value assumptions and methodology for assets and liabilities
Number of warrants (in shares)	13,000	13,000
CDTi stock price (in dollars per share)	$ 1.73	$ 4.70
Strike price (in dollars per share)	$ 6.10	$ 6.10
Expected volatility	85.00%	99.10%
Risk-free interest rate	0.60%	1.20%
Expected life in years	2 years	2 years 6 months
Warrants Issued July 3, 2013, Liability | November 23, 2015 Offering
Fair value assumptions and methodology for assets and liabilities
Number of warrants (in shares)	18,800	18,800
CDTi stock price (in dollars per share)	$ 1.73	$ 4.70
Strike price (in dollars per share)	$ 6.10	$ 6.10
Expected volatility	95.20%	95.50%
Risk-free interest rate	0.80%	1.50%
Expected life in years	3 years 4 months 24 days	3 years 10 months 24 days