Equity-Based Compensation - Schedule of Stock Options Rollforward (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Options
Outstanding beginning balance (in shares) | shares	5,697,714
Granted (in shares) | shares	2,630,248
Exercise of options (in shares) | shares	(78,139)
Forfeited (in shares) | shares	(510,042)
Outstanding ending balance (in shares) | shares	7,739,781	5,697,714
Weighted-Average Exercise Price
Outstanding beginning balance (in dollars per share) | $ / shares	$ 2.34
Granted (in dollars per share) | $ / shares	1.94
Exercised (in dollars per share) | $ / shares	0.88
Forfeited (in dollars per share) | $ / shares	2.67
Outstanding ending balance (in dollars per share) | $ / shares	$ 2.20	$ 2.34
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-Average Remaining Contractual Term (years)	6 years 8 months 12 days	6 years 8 months 12 days
Aggregate Intrinsic Value (thousands) | $	$ 2,090	$ 4,625
Exercisable (in shares) | shares	4,565,863
Exercisable, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.12
Exercisable, weighted-average remaining contractual term	4 years 10 months 24 days
Exercisable, aggregate intrinsic value | $	$ 1,657
Vested and expected to vest (in shares) | shares	7,739,781
Vested and expected to vest, weighted-average exercise price (in dollars per share) | $ / shares	$ 2.20
Weighted-Average Remaining Contractual Term (years)	6 years 8 months 12 days
Aggregate Intrinsic Value (thousands) | $	$ 2,090