Geographic / Customer Concentration - Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas (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 External Customer [Line Items]
Actual revenue	$ 102,161	$ 72,523	$ 75,609	$ 68,631	$ 75,326	$ 75,079	$ 69,555	$ 87,444	$ 318,924	$ 307,404	$ 532,938
United States
Revenue from External Customer [Line Items]
Actual revenue									139,162	119,159	194,184
South Korea
Revenue from External Customer [Line Items]
Actual revenue									113,189	112,291	113,059
Japan
Revenue from External Customer [Line Items]
Actual revenue									35,614	29,525	25,210
China
Revenue from External Customer [Line Items]
Actual revenue									11,103	309	77,087
Sweden
Revenue from External Customer [Line Items]
Actual revenue									6,934	6,933	6,935
France
Revenue from External Customer [Line Items]
Actual revenue									5,895	277	0
Other Europe
Revenue from External Customer [Line Items]
Actual revenue									5,810	5,116	6,305
Taiwan
Revenue from External Customer [Line Items]
Actual revenue									938	23,326	36,051
Other Asia
Revenue from External Customer [Line Items]
Actual revenue									279	468	0
Finland
Revenue from External Customer [Line Items]
Actual revenue									0	10,000	0
Canada
Revenue from External Customer [Line Items]
Actual revenue									$ 0	$ 0	$ 74,107