Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

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Credit Facilities (3.25% Convertible Senior Notes due 2020) (Details)		3 Months Ended
	Apr. 03, 2019 USD ($) day	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Aug. 09, 2018 USD ($)	Nov. 02, 2015 USD ($)
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt		$ (730,000)	$ 0
Convertible Senior Notes Due 2020
Debt Instrument [Line Items]
Debt instrument, stated interest rate				3.25%
Debt instrument face amount				$ 40,500,000.0
Convertible notes \| Convertible Senior Notes Due 2020
Debt Instrument [Line Items]
Debt instrument, stated interest rate					3.25%
Debt instrument face amount					$ 125,000,000
Convertible notes payable		100,000.0
Convertible notes \| 5% Note
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.00%		5.00%
Debt instrument face amount	$ 25,000,000.0
Convertible debt redemption, consecutive trading days threshold \| day	5
Convertible debt, conversion ratio	0.15129
Convertible notes payable		27,631,196
Debt issuance costs, gross		397,453
Convertible notes \| 5% Note \| Minimum
Debt Instrument [Line Items]
Periodic payment, interest		14,675,251.71
Convertible notes \| 5% Note \| Maximum
Debt Instrument [Line Items]
Periodic payment, interest		4,356,057.21
Revolving loan facility
Debt Instrument [Line Items]
Debt instrument, stated interest rate			5.50%
Gain (loss) on extinguishment of debt		$ (3,400,000)
Revolving loan facility \| Amended and Restated Facility Agreement
Debt Instrument [Line Items]
Debt instrument face amount				$ 40,500,000.0
Two Investors \| Convertible notes \| Convertible Senior Notes Issued November, 2015
Debt Instrument [Line Items]
Debt instrument face amount			$ 73,400,000.0
Two Investors \| Convertible notes \| 5% Note
Debt Instrument [Line Items]
Debt instrument face amount	$ 42,000,000.0