Debt and Warrants - Long-term Debt (Details) - USD ($)						3 Months Ended		4 Months Ended	9 Months Ended
	Aug. 01, 2018	Mar. 23, 2018	Jul. 07, 2017	Apr. 21, 2016	Aug. 31, 2015	Oct. 31, 2017	Sep. 30, 2017	Aug. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Mar. 01, 2016
Long-term debt
Current portion of long-term debt									$ 0		$ 1,609,244
Interest-only payments, term								4 months
Loan and security agreement
Long-term debt
Debt and unpaid accrued end-of-term payment											1,636,639
Unamortized note discount					$ 134,433						6,615
Unamortized debt issuance costs											(20,780)
Total											1,609,244
Current portion of long-term debt											$ 1,609,244
Nominal interest							$ 36,906		19,344	$ 183,040
Accretion of debt discount							7,712		20,779	29,351
Accretion of end-of-term payment							32,109		52,561	122,269
Accretion of debt issuance costs							24,038		6,616	91,562
Total							$ 100,765		$ 99,300	$ 426,222
Stand-by line of credit					8,000,000
Initial loan commitment					$ 6,000,000
Term of agreement					3 years
Interest rate (as a percent)												9.90%
Balloon amount payable on August 1, 2018	$ 600,000
Effective interest rate					15.00%
Repayment of loan from restricted cash				$ 1,500,000
Third Amendment
Long-term debt
Repayment of loan from restricted cash			$ 1,000,000
Interest-only payments, term						3 months
Principal paid		$ 689,345
Interest paid		4,471
Cash proceeds		$ 600,000