Segment Information and Foreign Operations - Concentration of Credit Risk (Details) - customer	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenues
Revenue, Major Customer [Line Items]
Number of customers representing significant share	1	2	2	2
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	10.00%	15.00%	13.00%	13.00%
Haisi Optoelectronics | Revenues
Revenue, Major Customer [Line Items]
Percentage share generated by major customers		18.00%		15.00%
Osram Opto [Member] | Revenues
Revenue, Major Customer [Line Items]
Percentage share generated by major customers			11.00%
Major Customer One | Accounts Receivable
Revenue, Major Customer [Line Items]
Percentage share generated by major customers			13.00%		14.00%
Major Customer Two | Accounts Receivable
Revenue, Major Customer [Line Items]
Percentage share generated by major customers			12.00%		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	5	5
Percentage share generated by major customers	30.00%	48.00%	39.00%	43.00%