UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Treasury Stock	Cumulative Effect, Period of Adoption, Adjustment	Total
Balance at Jun. 30, 2019	$ 4	$ 713,436	$ (40)		$ 22,447	$ (102,482)		$ 633,365
Balance (in shares) at Jun. 30, 2019	45,575,236					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)					(9,730)			(9,730)
Foreign currency translation adjustment			139					139
Stock-based compensation expense		5,594						5,594
Exercise of stock options		42						42
Exercise of stock options (in shares)	2,500
Issuance of restricted stock awards (in shares)	918,702
Forfeiture of restricted stock awards (in shares)	(34,090)
Repurchase of restricted stock for tax withholding		(4,698)						(4,698)
Repurchase of restricted stock for tax withholding (in shares)	(171,778)
Balance at Sep. 30, 2019	$ 4	714,374	99		12,717	$ (102,482)		624,712
Balance (in shares) at Sep. 30, 2019	46,290,570					(5,334,743)
Balance at Jun. 30, 2019	$ 4	713,436	(40)		22,447	$ (102,482)		633,365
Balance (in shares) at Jun. 30, 2019	45,575,236					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)								10,864
Repurchase of restricted stock for tax withholding								(4,883)
Balance at Dec. 31, 2019	$ 4	720,451	(188)		33,311	$ (102,482)		651,096
Balance (in shares) at Dec. 31, 2019	46,282,173					(5,334,743)
Balance at Sep. 30, 2019	$ 4	714,374	99		12,717	$ (102,482)		624,712
Balance (in shares) at Sep. 30, 2019	46,290,570					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)					20,594			20,594
Foreign currency translation adjustment			(287)					(287)
Stock-based compensation expense		6,256						6,256
Exercise of stock options		6						6
Exercise of stock options (in shares)	500
Issuance of restricted stock awards (in shares)	18,000
Forfeiture of restricted stock awards (in shares)	(18,019)
Repurchase of restricted stock for tax withholding		(185)						(185)
Repurchase of restricted stock for tax withholding (in shares)	(8,878)
Balance at Dec. 31, 2019	$ 4	720,451	(188)		33,311	$ (102,482)		651,096
Balance (in shares) at Dec. 31, 2019	46,282,173					(5,334,743)
Balance at Jun. 30, 2020	$ 4	730,761	93		46,953	$ (102,482)		675,329
Balance (in shares) at Jun. 30, 2020	46,341,627					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)					12,666			12,666
Foreign currency translation adjustment			(192)					(192)
Stock-based compensation expense		9,009						9,009
Exercise of stock options		32						32
Exercise of stock options (in shares)	948,867
Withholding of stock options for tax withholding		(10,885)						(10,885)
Withholding of stock options for tax withholding (in shares)	(655,219)
Equity component of convertible senior notes, net of issuance costs and taxes		105,477						105,477
Purchases of capped calls in connection with convertible senior notes		(60,354)						(60,354)
Issuance of restricted stock awards (in shares)	383,223
Forfeiture of restricted stock awards (in shares)	(9,329)
Repurchase of restricted stock for tax withholding		(5,808)						(5,808)
Repurchase of restricted stock for tax withholding (in shares)	(136,194)
Balance (ASU 2016-13) at Sep. 30, 2020				$ (6,253)			$ (6,253)
Balance at Sep. 30, 2020	$ 4	768,232	(99)		53,366	$ (102,482)		719,021
Balance (in shares) at Sep. 30, 2020	46,872,975					(5,334,743)
Balance at Jun. 30, 2020	$ 4	730,761	93		46,953	$ (102,482)		675,329
Balance (in shares) at Jun. 30, 2020	46,341,627					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)								$ 37,167
Exercise of stock options (in shares)								963,867
Purchases of capped calls in connection with convertible senior notes								$ (60,354)
Repurchase of restricted stock for tax withholding								(6,108)
Balance at Dec. 31, 2020	$ 4	777,409	(369)		77,867	$ (102,482)		752,429
Balance (in shares) at Dec. 31, 2020	46,893,934					(5,334,743)
Balance at Sep. 30, 2020	$ 4	768,232	(99)		53,366	$ (102,482)		719,021
Balance (in shares) at Sep. 30, 2020	46,872,975					(5,334,743)
Increase (Decrease) in Stockholders' Equity
Net income (loss)					24,501			24,501
Foreign currency translation adjustment			(270)					(270)
Stock-based compensation expense		9,181						9,181
Exercise of stock options		271						271
Exercise of stock options (in shares)	15,000
Equity component of convertible senior notes, net of issuance costs and taxes		25						25
Issuance of restricted stock awards (in shares)	19,500
Forfeiture of restricted stock awards (in shares)	(2,122)
Repurchase of restricted stock for tax withholding		(300)						(300)
Repurchase of restricted stock for tax withholding (in shares)	(11,419)
Balance at Dec. 31, 2020	$ 4	$ 777,409	$ (369)		$ 77,867	$ (102,482)		$ 752,429
Balance (in shares) at Dec. 31, 2020	46,893,934					(5,334,743)