Stock Incentive Plans - Stock-Based Compensation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock Based Compensation
Total stock-based compensation expense	$ 1,110,109	$ 680,094	$ 1,982,985	$ 1,416,791
Research and development expense
Stock Based Compensation
Total stock-based compensation expense	332,636	175,772	548,524	400,521
Sales and marketing expense
Stock Based Compensation
Total stock-based compensation expense	41,122	39,210	87,215	59,762
General and administrative expense
Stock Based Compensation
Total stock-based compensation expense	736,351	$ 465,112	1,347,246	$ 956,508
Stock options and RSUs
Stock Based Compensation
Unrecognized stock-based compensation expense	$ 5,555,383		$ 5,555,383
Expected weighted average period to be recognized			2 years 3 months 22 days
Minimum | Employee stock options
Estimated grant-date fair value of stock options calculated using the Black-Scholes option-pricing model
Weighted-average volatility (as a percent)			142.90%	95.60%
Weighted-average expected term (years)			5 years 7 months 6 days	5 years 9 months 18 days
Risk-free interest rate (as a percent)			1.50%	2.80%
Maximum | Employee stock options
Estimated grant-date fair value of stock options calculated using the Black-Scholes option-pricing model
Weighted-average volatility (as a percent)			145.90%	95.90%
Weighted-average expected term (years)			5 years 9 months 18 days
Risk-free interest rate (as a percent)			1.90%	3.10%