Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(4))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(g))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_ShortTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Principal Accounting Policies - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) ¥ in Thousands, $ in Thousands	Sep. 30, 2020 CNY (¥)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 CNY (¥)
Assets [Abstract]
Short-term Investments	¥ 28,526	$ 4,201	¥ 32,000
Liabilities [Abstract]
Put right liabilities	124,100	$ 18,278
Fair Value, Recurring [Member]
Assets [Abstract]
Short-term Investments	28,526		32,000
Liabilities [Abstract]
Put right liabilities	124,100
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Assets [Abstract]
Short-term Investments	28,526		¥ 32,000
Liabilities [Abstract]
Put right liabilities	¥ 124,100