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The price per share of the conversion feature embedded in the debt instrument.

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Convertible Debt - Narratives (Details)			6 Months Ended
Convertible Debt - Narratives (Details)	Jun. 02, 2020 USD ($)	Sep. 13, 2019 USD ($) $ / shares	Jul. 02, 2021 USD ($) day $ / shares	Jun. 26, 2020 USD ($)	Dec. 31, 2020 USD ($) $ / shares
Debt Instrument [Line Items]
Common Stock, Par or Stated Value Per Share \| $ / shares			$ 0.001		$ 0.001
Fair value of 2022 Notes used to settle 2020 Notes			$ 0	$ 44,357,000
Convertible Note due 2022
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 37,700,000		$ 37,707,000		$ 37,707,000
Common Stock, Par or Stated Value Per Share \| $ / shares			$ 0.001
Debt Instrument, Convertible, Conversion Ratio			173.9978
Debt Conversion, Converted Instrument, Amount			$ 1,000
Debt Instrument, Convertible, Conversion Price \| $ / shares			$ 5.75
Carrying amount of equity component	8,300,000
Fair Value of Liability Component - Convertible Notes	36,000,000.0
Debt Instrument, Unamortized Discount	$ 1,700,000		$ 1,020,000		1,357,000
Debt Instrument, Interest Rate, Stated Percentage	4.375%
Convertible Note due 2022 \| Stock price greater or equal 130 percent of Note Conversion Price [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days \| day			20
Debt Instrument, Convertible, Threshold Consecutive Trading Days \| day			30
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			130.00%
Convertible Note due 2022 \| Note price less than 98 percent of stock price times conversion rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days \| day			5
Debt Instrument, Convertible, Threshold Consecutive Trading Days \| day			5
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			98.00%
Convertible Note due 2024
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 115,500,000	$ 115,500,000		115,500,000
Common Stock, Par or Stated Value Per Share \| $ / shares		$ 0.001
Debt Instrument, Convertible, Conversion Ratio		115.5001
Debt Conversion, Converted Instrument, Amount		$ 1,000	1,000
Debt Instrument, Convertible, Conversion Price \| $ / shares		$ 8.66
Carrying amount of equity component		$ 24,900,000
Debt Instrument, Unamortized Discount			$ 16,982,000		$ 19,294,000
Debt Instrument, Interest Rate, Stated Percentage		2.00%
Convertible Note due 2024 \| Stock price greater or equal 130 percent of Note Conversion Price [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days \| day			20
Debt Instrument, Convertible, Threshold Consecutive Trading Days \| day			30
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			130.00%
Convertible Note due 2024 \| Note price less than 98 percent of stock price times conversion rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days \| day			5
Debt Instrument, Convertible, Threshold Consecutive Trading Days \| day			5
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger			98.00%
Convertible Debt \| Convertible Note due 2022
Debt Instrument [Line Items]
Fair value of 2022 Notes used to settle 2020 Notes	$ 44,400,000