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

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Convertible Notes (Summary of Convertible Notes) (Detail) $ / shares in Units, $ in Thousands		6 Months Ended
	Nov. 21, 2016	Jun. 30, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($)	Sep. 17, 2019 $ / shares	Nov. 22, 2016 $ / shares
Debt Instrument [Line Items]
Convertible Notes, Principal Balance Outstanding		$ 14,805
Convertible Notes Payable, Carrying Value		$ 13,507	$ 27,250
December 2021 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					2.75%
Debt Instrument, Convertible, Conversion Ratio	262.2951	316.5801
Convertible notes, conversion price (in Dollars per Share) \| $ / shares		$ 3.16		$ 3.81	$ 3.81
Convertible Notes, Maturity Date (Date)		Dec. 01, 2021
Convertible Notes, Principal Balance Outstanding		$ 13,805	19,170
Convertible Notes Payable, Carrying Value		$ 12,601	16,950
December 2024 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				2.75%
Convertible notes, conversion price (in Dollars per Share) \| $ / shares		$ 3.16		$ 3.81
Convertible Notes, Principal Balance Outstanding		$ 1,000	11,500
Convertible Notes Payable, Carrying Value		$ 906	$ 10,300