Commitments and contingencies (Details)	Apr. 11, 2014 USD ($)
Mentor lawsuit seeking rescission of co-operative funding agreement with Bhang Details:
Mentor filed suit against Bhang and its owners in the United States District Court for the Northern District of California for rescission of the February 28, 2014 co-operative funding agreement with Bhang, seeking return of the investment	$ 1,500,000