The Company and Summary of Significant Accounting Policies - Risks and Concentration of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2020 customer	Dec. 31, 2019 item customer	Dec. 31, 2018 customer item
Accounts Receivable
The Company and Summary of Significant Accounting Policies
Number of customers representing significant share	2	3
Raw Materials | Revenues
The Company and Summary of Significant Accounting Policies
Number of customers representing significant share	1	3	3
Landmark | Revenues
The Company and Summary of Significant Accounting Policies
Number of customers representing significant share	1	1	1
Percentage share generated by major customers (in hundredths)	11.00%	15.00%	13.00%
Major Customer One | Accounts Receivable
The Company and Summary of Significant Accounting Policies
Percentage share generated by major customers (in hundredths)	11.00%	14.00%
Major Customer Two | Accounts Receivable
The Company and Summary of Significant Accounting Policies
Percentage share generated by major customers (in hundredths)	10.00%	13.00%
Major Customer Three | Accounts Receivable
The Company and Summary of Significant Accounting Policies
Percentage share generated by major customers (in hundredths)		12.00%
Top Five Major Customers | Revenues
The Company and Summary of Significant Accounting Policies
Number of customers representing significant share	5	5	5
Percentage share generated by major customers (in hundredths)	32.00%	40.00%	35.00%