Carrying Amounts and Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financial assets
Cash and cash equivalents	$ 38,794	$ 41,455
Accounts receivable	199	265
Refundable deposits	192	211
Investment in securities - current	7,950
Investment in securities - noncurrent	2,371	10,322
Financial liabilities
Accounts payable	53	118
Accrued expenses	1,151	1,435
Lease liabilities - current and noncurrent	1,333	1,987
Carrying Amount
Financial assets
Cash and cash equivalents	38,794	41,455
Accounts receivable	199	265
Restricted cash	313	306
Refundable deposits	192	211
Investment in securities - current	7,950
Investment in securities - noncurrent	2,371	10,322
Financial liabilities
Accounts payable	53	118
Accrued expenses	1,151	1,435
Lease liabilities - current and noncurrent	1,333	1,987
Estimated Fair Value
Financial assets
Cash and cash equivalents	38,794	41,455
Accounts receivable	199	265
Restricted cash	313	306
Refundable deposits	192	211
Investment in securities - current	7,950
Investment in securities - noncurrent	2,371	10,322
Financial liabilities
Accounts payable	53	118
Accrued expenses	1,151	1,435
Lease liabilities - current and noncurrent	$ 1,333	$ 1,987

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment after one year or beyond the operating cycle, if longer.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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

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