Stockholders’ Equity and Stock-Based Compensation - Warrant Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Shares of Stock under Warrants
Beginning balance (in shares)	24,406
Granted (in shares)	95,396
Exercised (in shares)	(90,093)
Canceled (in shares)	0
Ending balance (in shares)	29,709	24,406
Vested and exercisable (in shares)	29,709
Weighted- Average Exercise Price
Beginning balance (in USD per share)	$ 1.76
Granted (in USD per share)	0.22
Exercised (in USD per share)	0.21
Ending balance (in USD per share)	1.54	$ 1.76
Vested and exercisable (in USD per share)	$ 1.54
Weighted- Average Remaining Contractual Term
Balance	4 years 1 month 9 days	4 years 9 months 25 days
Granted	4 years 6 months 10 days
Vested and exercisable	4 years 1 month 9 days
Aggregate Intrinsic Value
Beginning balance	$ 7,933
Exercised	37,150
Ending balance	1,813	$ 7,933
Vested and exercisable	$ 0