Note C - Revenue Recognition - Revenue by Major Product Category (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer, Excluding Assessed Tax, Total	$ 48,658	$ 46,084	$ 43,411	$ 52,719	$ 58,018	$ 56,386	$ 87,822	$ 65,239	$ 190,872	$ 267,465	$ 382,329
Percent of Revenue									100.00%	100.00%	100.00%
Data Center [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total									$ 143,563	$ 200,236	$ 306,712
Percent of Revenue									75.20%	74.90%	80.20%
CATV [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total									$ 37,328	$ 51,699	$ 60,756
Percent of Revenue									19.60%	19.30%	15.90%
Telecom [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total									$ 8,429	$ 13,159	$ 12,899
Percent of Revenue									4.40%	4.90%	3.40%
FTTH [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total									$ 190	$ 818	$ 490
Percent of Revenue									0.10%	0.30%	0.10%
Product and Service, Other [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total									$ 1,362	$ 1,553	$ 1,472
Percent of Revenue									0.70%	0.60%	0.40%