Common Stock and Preferred Stock - Additional Information (Detail)		1 Months Ended			3 Months Ended					9 Months Ended		12 Months Ended
	Aug. 09, 2019 USD ($) $ / shares shares	Aug. 31, 2019 USD ($) $ / shares shares	Jan. 31, 2019 USD ($) director shares	Jan. 31, 2018 USD ($) ExecutiveOfficers shares	Sep. 30, 2019 USD ($) shares	Jun. 30, 2019 USD ($) shares	Mar. 31, 2019 USD ($) ExecutiveOfficers shares	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) shares
Class of Stock [Line Items]
Common stock issued in the period (in shares) | shares	5,853,002
Dividends | $					$ 0			$ 0		$ 0	$ 0
Stock issuance and grants | $	$ 4,200,000				4,214,000				$ 3,000
Shares vested | shares		164,166
Shares forfeited | shares										54,704
Stock repurchased (in shares) | shares		3,112,840
Share price (in dollars per share) | $ / shares		$ 7.71
Stock repurchased | $		$ 24,000,000
Preferred stock dividends | $					180,000					$ 180,000
Temporary equity | $					180,000					180,000		$ 0
Dividends payable | $					$ 180,000					$ 180,000
Executive officer
Class of Stock [Line Items]
Restricted stock issued (in shares) | shares			3,061,224	1,914,894
Restricted stock issued, value | $			$ 4,500,000	$ 4,500,000
Number of executive officers			2	2			2
Executive officer | Restricted Stock
Class of Stock [Line Items]
Vesting period				3 years
Shares surrendered (in shares) | shares						24,281	143,913					42,346
Value of shares surrendered | $						$ 25,000	$ 215,000					$ 98,000
Non-employee directors
Class of Stock [Line Items]
Restricted stock issued (in shares) | shares			328,230	249,480
Restricted stock issued, value | $			$ 500,000	$ 600,000
Number of non-employee directors | director			6
Redeemable Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares) | shares	200,000
Preferred stock par value (USD per share) | $ / shares	$ 0.001
Preferred shares outstanding (in shares) | shares					200,000					200,000
Initial value per share (USD per share) | $ / shares	$ 100
Preferred stock quarterly dividend rate	6.00%
Number of shares outstanding in which, one director may be elected | shares	50,000
Voting percentage required to change number of directors	80.00%
Minimum | Restricted Stock
Class of Stock [Line Items]
Vesting period										1 year
Minimum | Redeemable Preferred Stock
Class of Stock [Line Items]
Preferred stock, liquidation preference percent	20.00%
Accretion percentage	20.00%
Maximum | Restricted Stock
Class of Stock [Line Items]
Vesting period										5 years
Maximum | Redeemable Preferred Stock
Class of Stock [Line Items]
Preferred stock, liquidation preference percent	150.00%
Accretion percentage	150.00%
Fair Value Measurements, Recurring | Redeemable Preferred Stock | Carrying Amount
Class of Stock [Line Items]
Convertible senior notes | $					$ 4,894,000					$ 4,894,000