Note to Schedule One - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Reserves and registered capital of PRC subsidiaries	$ 399,340,000	$ 376,500,000
Minimum percentage of restricted net assets of consolidated and unconsolidated subsidiaries to consolidated net assets to file condensed financial information	25.00%
Cash dividend was declared by subsidiaries	$ 0	0	$ 0
Cash dividend was paid by subsidiaries	$ 0	$ 0	$ 0

Amount of dividends declared by the affiliates to the Parent, during the period.

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Amount of dividends paid by the affiliates to the Parent, during the period.

+ References

No definition available.

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- Definition

Minimum percentage of restricted net assets of consolidated and unconsolidated subsidiaries to consolidated net assets to file condensed financial information.

+ References

No definition available.

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- References

No definition available.

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- Definition

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

+ References

Reference 1: 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)(23)(c))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

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