Commitments and Contingencies - Purchase Commitments (Details) - USD ($)		9 Months Ended
	Sep. 05, 2017	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2017
Purchase Commitment, Excluding Long-term Committment [Line Items]
Payments to Acquire Intangible Assets		$ 14,034,000	$ 0
Raw materials, wafers, and packaging and testing services puchase commitments
Purchase Commitment, Excluding Long-term Committment [Line Items]
Purchase commitment, amount		38,400,000		$ 25,700,000
Property and equipment purchase commitments
Purchase Commitment, Excluding Long-term Committment [Line Items]
Purchase commitment, amount		89,600,000		69,200,000
License fees | STMicro
Purchase Commitment, Excluding Long-term Committment [Line Items]
Payments to Acquire Intangible Assets	$ 17,000,000	13,500,000
Intangible assets		16,400,000
Indemnification Agreement
Purchase Commitment, Excluding Long-term Committment [Line Items]
Indemnifications accrual		$ 0		$ 0