The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

Share-Based Compensation - Reconciliation of Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares)	771,000	771,000
Granted (in shares)	210,400	210,000	57,800	125,700
Exercised (in shares)		(5,000)
Forfeited (in shares)	(201,000)
Ending balance (in shares)		775,000	771,000
Exercisable (in shares)		530,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance (in usd per share)	$ 15.17	$ 15.17
Granted (in usd per share)		7.93
Exercised (in usd per share)		4.42
Forfeited (in usd per share)		11.96
Ending balance (in usd per share)		13.24	$ 15.17
Exercisable (in usd per share)		$ 14.23
Weighted-Average Remaining Contractual Term, Outstanding		5 years 6 months
Weighted- Average Remaining Contractual Term, Options exercisable		4 years
Aggregate Intrinsic Value, Exercised		$ 7	$ 500	$ 3,800
Aggregate Intrinsic Value, Outstanding		291
Aggregate Intrinsic Value, Options exercisable		$ 30