Supplemental Balance Sheet Information - Schedule of Other Non-current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other non-current assets
Goodwill	$ 109	$ 109
Prepayment of property and equipment	16,984	10,289
Payment of facility capacity expansion activities	29,778	24,881
Prepaid VAT	10,913	29,967
Rental deposits and other	5,962	3,209
Long-term investments	49,344	0
Total	$ 113,090	$ 68,455