STOCK-BASED COMPENSATION

6 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

STOCK-BASED COMPENSATION

NOTE 10 STOCK-BASED COMPENSATION

A summary of compensation cost for stock-based payment arrangements recognized in drilling services operating expense, research and development expense and selling, general and administrative expense on our Unaudited Condensed Consolidated Statements of Operations is as follows:

	Three Months Ended March 31,				Six Months Ended March 31,
(in thousands)	2021		2020		2021		2020
Stock-based compensation expense
Drilling services operating	$	1,529	$	2,651	$	3,292	$	4,887
Research and development	271		181		607		347
Selling, general and administrative	5,026		7,918		10,378		15,718
	$	6,826	$	10,750	$	14,277	$	20,952

Restricted Stock

A summary of the status of our restricted stock awards as of March 31, 2021 and changes in non-vested restricted stock outstanding during the six months then ended is presented below:

(in thousands, except per share amounts)	Shares (1)	Weighted Average Grant Date Fair Value per Share
Non-vested restricted stock outstanding at September 30, 2020	1,280	$	49.81
Granted	698	25.60
Vested (2)	(528)	51.73
Forfeited	(17)	36.18
Non-vested restricted stock outstanding at March 31, 2021	1,433	$	37.45

(1)    Restricted stock shares include restricted phantom stock units under our Director Deferred Compensation Plan. These phantom stock units confer the economic benefits of owning company stock without the actual ownership, transfer or issuance of any shares. During the six months ended March 31, 2021, 18,906 restricted phantom stock units were granted and 20,616 restricted phantom stock units vested during the same period.

(2)    The number of restricted stock awards vested includes shares that we withheld on behalf of our employees to satisfy the statutory tax withholding requirements.

Performance Units

A summary of the status of our performance-vested restricted share units (performance units) as of March 31, 2021 and changes in non-vested performance units outstanding during the six months then ended is presented below:

(in thousands, except per share amounts)	Performance Units	Weighted Average Grant Date Fair Value per Performance Unit
Non-vested performance units outstanding at September 30, 2020	337	$	51.09
Granted	313	29.77
Dividend equivalent right performance units credited	48	51.79
Forfeited	(11)	43.40
Non-vested performance units outstanding at March 31, 2021 (1)	687	$	41.55

(1)    Of the total non-vested performance units at the end of the period, specified performance criteria has been achieved with respect to 86,904 performance units which is calculated based on the payout percentage for the completed performance period. The vesting and number of the remainder of non-vested performance units reflected at the end of the period is contingent upon our achievement of specified target performance criteria. If we meet the specified maximum performance criteria, approximately 644,188 additional performance units could vest or become eligible to vest.