Segment Information and Foreign Operations - Segment and Geographical Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Information and Foreign Operations
Number of operating segments | segment	1
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	$ 22,688	$ 19,405
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	165,779		$ 169,147
China
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	164,217		167,516
North America (primarily the United States)
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	1,562		$ 1,631
Reportable Geographical Components
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	22,688	19,405
Reportable Geographical Components | China
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	11,517	8,102
Reportable Geographical Components | Taiwan
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	4,582	2,471
Reportable Geographical Components | Japan
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	990	1,535
Reportable Geographical Components | Asia Pacific (excluding China, Taiwan and Japan)
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	798	1,091
Reportable Geographical Components | Europe (primarily Germany)
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	3,725	3,570
Reportable Geographical Components | North America (primarily the United States)
Net revenues reported for products shipped to customers in corresponding geographic region
Revenue	$ 1,076	$ 2,636