Convertible Preferred Stock and Stockholders' Equity - Summary of Option and Stock Appreciation Rights Outstanding by Range of Exercise Price (Details) - Stock Options and Stock Appreciation Rights (SARs) [Member]	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding | shares	1,857,599
Weighted Average Remaining Life	8 years 2 months 5 days
Weighted Average Exercise Price	$ 2.22
Number of Options Currently Exercisable | shares	523,982
Weighted Average Exercise Price per Vested Share	$ 3.54
Range of Exercise Prices One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	0.00
Range of Exercise Price, Upper Limit	$ 1.00
Options Outstanding | shares	656,444
Weighted Average Remaining Life	8 years 2 months 1 day
Weighted Average Exercise Price	$ 0.74
Number of Options Currently Exercisable | shares	265,366
Weighted Average Exercise Price per Vested Share	$ 0.74
Range of Exercise Prices Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	1.01
Range of Exercise Price, Upper Limit	$ 2.00
Options Outstanding | shares	96,333
Weighted Average Remaining Life	6 years 9 months 11 days
Weighted Average Exercise Price	$ 1.50
Number of Options Currently Exercisable | shares	62,794
Weighted Average Exercise Price per Vested Share	$ 1.73
Range of Exercise Prices Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	2.01
Range of Exercise Price, Upper Limit	$ 4.00
Options Outstanding | shares	957,477
Weighted Average Remaining Life	8 years 9 months 29 days
Weighted Average Exercise Price	$ 2.05
Number of Options Currently Exercisable | shares	83,477
Weighted Average Exercise Price per Vested Share	$ 2.15
Range of Exercise Prices Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	4.01
Range of Exercise Price, Upper Limit	$ 10.00
Options Outstanding | shares	117,500
Weighted Average Remaining Life	5 years 11 months 8 days
Weighted Average Exercise Price	$ 4.17
Number of Options Currently Exercisable | shares	82,500
Weighted Average Exercise Price per Vested Share	$ 4.04
Range of Exercise Prices Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	10.01
Range of Exercise Price, Upper Limit	$ 20.00
Options Outstanding | shares
Weighted Average Remaining Life	0 years
Weighted Average Exercise Price
Number of Options Currently Exercisable | shares
Weighted Average Exercise Price per Vested Share	$ 0.00
Range of Exercise Prices Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Lower Limit	30.01
Range of Exercise Price, Upper Limit	$ 40.00
Options Outstanding | shares	29,845
Weighted Average Remaining Life	10 months 28 days
Weighted Average Exercise Price	$ 34.73
Number of Options Currently Exercisable | shares	29,845
Weighted Average Exercise Price per Vested Share	$ 34.73