Segment Information and Foreign Operations - Concentration of Credit Risk (Details) - Customer concentration	3 Months Ended
	Mar. 31, 2021 customer	Mar. 31, 2020 customer
Revenues
Revenue, Major Customer [Line Items]
Number of customers representing significant share	0	2
Percentage share generated by major customers	10.00%
Accounts Receivable
Revenue, Major Customer [Line Items]
Number of customers representing significant share	2	3
Landmark | Revenues
Revenue, Major Customer [Line Items]
Percentage share generated by major customers		17.00%
Osram | Revenues
Revenue, Major Customer [Line Items]
Percentage share generated by major customers		15.00%
Major Customer One | Accounts Receivable
Revenue, Major Customer [Line Items]
Percentage share generated by major customers	14.00%	20.00%
Major Customer Two | Accounts Receivable
Revenue, Major Customer [Line Items]
Percentage share generated by major customers	10.00%	13.00%
Major Customer Three | Accounts Receivable
Revenue, Major Customer [Line Items]
Percentage share generated by major customers		12.00%
Top Five Major Customers | Revenues
Revenue, Major Customer [Line Items]
Number of customers representing significant share	5	5
Percentage share generated by major customers	26.00%	49.00%