Revenue Recognition - Summary of Net Revenues Disaggregated by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 74,196	$ 57,709	$ 139,465	$ 112,171
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	26,419		52,042
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	6,152		11,525
Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	40,263		73,619
All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,362		2,279
BBU [Member]
Disaggregation of Revenue [Line Items]
Revenue	48,349		88,986
BBU [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	18,295		35,286
BBU [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	4,877		9,602
BBU [Member] | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	23,876		42,087
BBU [Member] | All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,301		2,011
VI Chip [Member]
Disaggregation of Revenue [Line Items]
Revenue	19,890		40,029
VI Chip [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	7,771		15,770
VI Chip [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,169		1,742
VI Chip [Member] | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	10,905		22,292
VI Chip [Member] | All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	45		225
Picor [Member]
Disaggregation of Revenue [Line Items]
Revenue	5,957		10,450
Picor [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	353		986
Picor [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	106		181
Picor [Member] | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	5,482		9,240
Picor [Member] | All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 16		$ 43