Annual report pursuant to Section 13 and 15(d)

Income taxes - Provision (benefit) for income taxes using the statutory federal tax rate (Details)

v3.10.0.1
Income taxes - Provision (benefit) for income taxes using the statutory federal tax rate (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
US federal statutory income tax rate (benefit) (34.00%) (34.00%) 34.00%
State income taxes, net of federal benefit (2.70%) (0.40%) (0.60%)
Change in fair value of derivative liability (10.30%) (28.50%) 0.10%
Permanent differences 0.10% 1.00% 2.50%
Foreign Tax Rate Differential 2.00% 2.10% 0.20%
Research tax credit 0.00% (1.70%) (2.30%)
Tax reform impact on deferred taxes 97.80%    
Other 1.40% 7.30% 1.80%
Change in valuation allowance (51.40%) 50.80% 33.60%
Effective rate 0.00% 0.00% 0.00%