Stock-Based Compensation - Summarizes Information Concerning Options Outstanding and Options Vested and Exercisable (Details)	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options (in shares) | shares	13,975,671
Number of options (in shares) | shares	8,919,741
$1.01 – $1.55
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range (in dollars per share)	$ 1.01
Exercise price upper range (in dollars per share)	$ 1.55
Number of options (in shares) | shares	6,832,730
Weighted Average Remaining Contractual Life	7 years 11 months 29 days
Weighted average exercise price (in dollars per share)	$ 1.47
Number of options (in shares) | shares	3,223,605
Weighted Average Remaining Contractual Life	3 years 2 months 7 days
Weighted average exercise price (in dollars per share)	$ 1.42
$1.56 – $1.98
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range (in dollars per share)	1.56
Exercise price upper range (in dollars per share)	$ 1.98
Number of options (in shares) | shares	2,685,058
Weighted Average Remaining Contractual Life	4 years 8 months 22 days
Weighted average exercise price (in dollars per share)	$ 1.72
Number of options (in shares) | shares	2,499,294
Weighted Average Remaining Contractual Life	4 years 1 month 10 days
Weighted average exercise price (in dollars per share)	$ 1.72
$2.06 – $3.84
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range (in dollars per share)	2.06
Exercise price upper range (in dollars per share)	$ 3.84
Number of options (in shares) | shares	4,457,883
Weighted Average Remaining Contractual Life	7 years 2 months 26 days
Weighted average exercise price (in dollars per share)	$ 2.26
Number of options (in shares) | shares	3,196,842
Weighted Average Remaining Contractual Life	4 years 11 months 13 days
Weighted average exercise price (in dollars per share)	$ 2.26