Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Deficit (unaudited) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Series C Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Balance at Dec. 31, 2018	$ (107,074)				$ 4,377	$ (111,451)
Temporary equity balance, Shares at Dec. 31, 2018		209,119,674
Temporary equity balance, Value at Dec. 31, 2018		$ 130,353
Balance, Shares at Dec. 31, 2018				170,156
Accretion of convertible preferred stock to redemption value	(77)				(77)
Temporary equity, Accretion of convertible preferred stock to redemption value		$ 77
Stock-based compensation	48				48
Net loss	(3,589)					(3,589)
Balance at Mar. 31, 2019	(110,692)				4,348	(115,040)
Temporary equity balance, Shares at Mar. 31, 2019		209,119,674
Temporary equity balance, Value at Mar. 31, 2019		$ 130,430
Balance, Shares at Mar. 31, 2019				170,156
Balance at Dec. 31, 2019	(123,338)				4,419	(127,757)
Temporary equity balance, Shares at Dec. 31, 2019		209,119,674
Temporary equity balance, Value at Dec. 31, 2019	130,666	$ 130,666
Balance, Shares at Dec. 31, 2019				230,860
Issuance of Series C redeemable convertible preferred stock, net of issuance costs			$ 29,446
Issuance of Series C redeemable convertible preferred stock, net of issuance costs, Shares			78,306,611
Issuance of common stock warrants in conjunction with sale of Series C redeemable convertible preferred stock	740				740
Accretion of convertible preferred stock to redemption value	(85)				(85)
Temporary equity, Accretion of convertible preferred stock to redemption value		$ 85
Stock-based compensation	134				134
Net loss	(4,232)					(4,232)
Balance at Mar. 31, 2020	(126,781)				$ 5,208	$ (131,989)
Temporary equity balance, Shares at Mar. 31, 2020		287,426,285	78,306,611
Temporary equity balance, Value at Mar. 31, 2020	$ 160,197	$ 160,197	$ 29,452
Balance, Shares at Mar. 31, 2020				230,860