Convertible Senior Notes, Warrants, and Hedges - Net Carrying Amount Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Convertible Debt Carrying Amount [Roll Forward]
Net carrying amount, beginning of period			$ 299,551
Net carrying amount, end of period	$ 306,827		306,827
Convertible debt
Convertible Debt Carrying Amount [Roll Forward]
Contractual interest expense			1,600	$ 1,600
Convertible debt \| 0.875% Convertible Senior Notes Due 2022
Convertible Debt Carrying Amount [Roll Forward]
Contractual interest expense	827	$ 827	1,654	1,653
Amortization of debt discount	3,391	3,210	6,736	6,377
Amortization of debt issuance costs	270	270	540	540
Total	4,488	$ 4,307	8,930	$ 8,570
Net carrying amount, beginning of period			299,551
Net carrying amount, end of period	$ 306,827		$ 306,827

Convertible Debt Carrying Amount [Roll Forward]

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- Definition

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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- Definition

Amount of amortization expense attributable to debt issuance costs.

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- Definition

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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