Other Current Assets and Other Long-Term Assets - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other long-term assets	$ 9,157	$ 5,435
Deposits paid for research and development	8,600	5,100
Letter of credit secured by restricted cash	600
Restricted cash included in other long-term assets	$ 620	$ 321	$ 0