XML 52 R39.htm IDEA: XBRL DOCUMENT
v3.22.4

Intangible assets, net (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2021
Intangible assets, net |
Schedule of intangible assets, net | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | December 31, |  | December 31,
​ | ​ | 2021 | ​ | 2020
Software | ​ | $ | 30,838 | ​ | $ | 25,957
Land use rights* | ​ |  | 314,456 | ​ |  | 307,241
Patents | ​ |  | 4,707,000 | ​ |  | 4,599,000
Subtotal | ​ |  | 5,052,294 | ​ |  | 4,932,198
Less: Accumulated amortization | ​ |  | (4,846,323) | ​ |  | (4,268,165)
Intangible assets, net | ​ | $ | 205,971 | ​ | $ | 664,033
*There is no private ownership of land in China. Land is usually owned by the local government and the government grants land use rights for specified terms. The Company acquired land use rights from the local government in December 2002 for period of 50 years. As of December 31, 2021 and 2020, land use rights with net book value of $200,204 and $201,755, respectively, were pledged as collateral for bank loans (Note 12).

X
- References No definition available. + Details
Name: | us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of goodwill and intangible assets, which may be broken down by segment or major class. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
Name: | us-gaap_ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration