CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Accounts receivable, allowance for credit losses (in dollars)	$ 2,115	$ 1,771
Liabilities and stockholders' equity
Installment payment agreement, current portion, net of discounts	$ 291	$ 350
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	47,279,201	46,840,434
Common stock, shares outstanding	47,279,201	46,840,434
Senior secured 2022 notes
Liabilities and stockholders' equity
Unamortized debt costs	$ 3,365	$ 1,410
Unamortized debt premium	767	985
Senior unsecured 2024 notes
Liabilities and stockholders' equity
Unamortized debt costs	1,480	1,897
Unamortized debt premium	1,183	$ 0
Senior unsecured 2021 notes
Liabilities and stockholders' equity
Unamortized debt costs	$ 857

Amount of allowance for credit loss on accounts receivable, classified as current.

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