Stockholders' Equity, Convertible Preferred Stock and Redeemable Non-controlling Interest - Additional Information (Details) $ / shares in Units, $ in Thousands, ¥ in Millions		3 Months Ended	9 Months Ended			12 Months Ended
	Apr. 03, 2020 USD ($) shares	Mar. 31, 2020 CNY (¥)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 CNY (¥)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2020 CNY (¥) shares	Jun. 30, 2020 USD ($) shares	Jun. 09, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Mar. 05, 2019 shares
Stockholders Equity [Line Items]
Common Stock, Value, Issued			$ 239							$ 150
Common stock, shares authorized | shares			1,500,000,000				1,500,000,000			1,500,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.001							$ 0.001
Common shares kept in escrow account | shares											25,500,000
Proceeds from Issuance or Sale of Equity			$ 39,128		$ 2,500
Proceeds from Issuance of Common Stock						$ 1,100
Qingdao Xingyang City Investment [Member]
Stockholders Equity [Line Items]
Capital subscription agreement			28,000				¥ 200.0
First capital contribution | ¥		¥ 50.0
Remaining capital contribution			21,000	¥ 150.0
Installments of remaining capital contribution			$ 7,000	¥ 50.0
Dividend rate			6.00%	6.00%
SEDA | YA II PN, Ltd.
Stockholders Equity [Line Items]
Shares, Issued | shares								34,500,000
Common Stock, Value, Issued								$ 32,500
Common Stock, Share Price Calculated As A Percentage Of Market Price	90.00%
Installments of remaining capital contribution	$ 1,000
Percentage of Common Stock Shares Held, Limit for Not Requesting Advances	4.99%
Shares Equivalent To Commitment Fee | shares	1,000,000.0
Commitment Shares, Value , Deferred Offering Costs and Additional Paid in Capital								$ 900
Common Stock, Value Authorized	$ 50,000								$ 45,000
Common Stock, Period During Which The Entity Is Authorized To Sell	36 months
Convertible preferred stock
Stockholders Equity [Line Items]
Preferred stock, shares authorized | shares			50,000,000.0				50,000,000.0
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.001