Segment Information and Foreign Operations - Segment and Geographical Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2025 USD ($) segment	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Information and Foreign Operations
Number of operating segments | segment	1
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	$ 19,356	$ 22,688
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	161,388		$ 162,200
CHINA
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	160,107		160,847
North America (primarily the United States)
Long-lived assets by geographic region, net of depreciation:
Long-lived assets	1,281		$ 1,353
Reportable Geographical Components [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	19,356	22,688
Reportable Geographical Components [Member] | CHINA
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	13,426	11,517
Reportable Geographical Components [Member] | TAIWAN
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	1,221	4,582
Reportable Geographical Components [Member] | JAPAN
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	718	990
Reportable Geographical Components [Member] | Asia Pacific (excluding China, Taiwan and Japan)
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	781	798
Reportable Geographical Components [Member] | Europe (primarily Germany)
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	2,101	3,725
Reportable Geographical Components [Member] | North America (primarily the United States)
Geographic Areas, Revenues from External Customers [Abstract]
Revenue	$ 1,109	$ 1,076