Balance Sheet Components - Accrued Expenses (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Accrued compensation and related:
Accrued vacation	$ 231,718	$ 223,769
Accrued payroll	265	2,692
Accrued payroll tax	19,769	20,140
Total of accrued compensation and related	251,752	246,601
Accrued interest	124,239	123,982
Accrued clinical	78,822	36,725
Accrued legal costs	249,998	92,500
Accrued audit		37,000
Accrued other	156,040	45,714
Total	$ 860,851	$ 582,522