Supplemental Information to Consolidated Statements of Cash Flows - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	2 Months Ended	3 Months Ended		12 Months Ended
	Aug. 09, 2019	Jun. 30, 2017	Feb. 28, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flow Supplemental Disclosures [Line Items]
Common stock issued in the period (in shares)	5,853,002
Stock issuance and grants	$ 4,200					$ 4,214
Preferred stock, shares issued (in shares)	200,000					200,000	0
Preferred stock, par value (in dollars per share)	$ 0.001					$ 0.001	$ 0.001
4.25% Convertible Senior Notes Due 2018
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument shares common stock issued upon conversion (in shares)					2,900,000
Common Stock
Cash Flow Supplemental Disclosures [Line Items]
Restricted stock surrendered, (in shares)						55,000		9,000
Common stock issued in the period (in shares)						5,853,000
Stock issuance and grants						$ 6
Common Stock | 4.25% Convertible Senior Notes Due 2018
Cash Flow Supplemental Disclosures [Line Items]
Debt instrument shares common stock issued upon conversion (in shares)		112,400	2,865,000	112,400				3,000,000
Common stock shares issued upon conversion of debt instrument, value		$ 400	$ 15,100					$ 15,500
Employees - including an executive officer
Cash Flow Supplemental Disclosures [Line Items]
Restricted stock surrendered, (in shares)						143,910	42,346	29,689
Employees - including an executive officer | Maximum
Cash Flow Supplemental Disclosures [Line Items]
Restricted stock surrendered, in values						$ 100	$ 100	$ 100
Redeemable Preferred Stock
Cash Flow Supplemental Disclosures [Line Items]
Preferred stock, shares issued (in shares)	200,000
Carrying Amount
Cash Flow Supplemental Disclosures [Line Items]
Convertible senior notes						5,247
Carrying Amount | Fair Value Measurements, Recurring | Redeemable Preferred Stock
Cash Flow Supplemental Disclosures [Line Items]
Convertible senior notes	$ 4,900					$ 5,200