CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance (in shares) at Dec. 31, 2017		19,310,000
Balance at Dec. 31, 2017	$ 130,791	$ 96	$ 142,196	$ (164)	$ (11,337)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of shares withheld for tax payments	485		485
Unrealized gain (loss) on derivative financial instruments, net of tax	83			83
Net income (loss)	161				161
Balance (in shares) at Mar. 31, 2018		19,310,000
Balance at Mar. 31, 2018	131,126	$ 96	142,681	(81)	(11,570)
Balance (in shares) at Dec. 31, 2017		19,310,000
Balance at Dec. 31, 2017	130,791	$ 96	142,196	(164)	(11,337)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on derivative financial instruments, net of tax	167
Net income (loss)	4,674
Balance (in shares) at Sep. 30, 2018		19,382,000
Balance at Sep. 30, 2018	136,632	$ 97	143,589	3	(7,057)
Balance (in shares) at Mar. 31, 2018		19,310,000
Balance at Mar. 31, 2018	131,126	$ 96	142,681	(81)	(11,570)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under stock plans, net of shares withheld for tax payments (in shares)		23,000
Issuance of shares under stock plans, net of shares withheld for tax payments	206	$ 0	206
Stock-based compensation, net of shares withheld for tax payments (in shares)		29,000
Stock-based compensation, net of shares withheld for tax payments	202	$ 1	201
Unrealized gain (loss) on derivative financial instruments, net of tax	46			46
Tax payments related to stock-based awards	(84)		(84)
Net income (loss)	4,452				4,452
Balance (in shares) at Jun. 30, 2018		19,362,000
Balance at Jun. 30, 2018	135,948	$ 97	143,004	(35)	(7,118)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under stock plans, net of shares withheld for tax payments (in shares)		20,000
Issuance of shares under stock plans, net of shares withheld for tax payments	221	$ 0	221
Stock-based compensation, net of shares withheld for tax payments (in shares)		0
Stock-based compensation, net of shares withheld for tax payments	372	$ 0	372
Unrealized gain (loss) on derivative financial instruments, net of tax	38			38
Tax payments related to stock-based awards	(8)		(8)
Net income (loss)	61				61
Balance (in shares) at Sep. 30, 2018		19,382,000
Balance at Sep. 30, 2018	$ 136,632	$ 97	143,589	3	(7,057)
Balance (in shares) at Dec. 31, 2018	19,382,641	19,383,000
Balance at Dec. 31, 2018	$ 136,435	$ 97	144,013	(86)	(7,589)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of shares withheld for tax payments (in shares)		29,000
Stock-based compensation, net of shares withheld for tax payments	418	$ 0	418
Unrealized gain (loss) on derivative financial instruments, net of tax	(47)			(47)
Tax payments related to stock-based awards	(157)		(157)
Net income (loss)	(7,364)				(7,364)
Balance (in shares) at Mar. 31, 2019		19,412,000
Balance at Mar. 31, 2019	$ 129,285	$ 97	144,274	(133)	(14,953)
Balance (in shares) at Dec. 31, 2018	19,382,641	19,383,000
Balance at Dec. 31, 2018	$ 136,435	$ 97	144,013	(86)	(7,589)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on derivative financial instruments, net of tax	(161)
Net income (loss)	$ (5,978)
Balance (in shares) at Sep. 30, 2019	19,465,244	19,466,000
Balance at Sep. 30, 2019	$ 131,559	$ 97	145,276	(247)	(13,567)
Balance (in shares) at Mar. 31, 2019		19,412,000
Balance at Mar. 31, 2019	129,285	$ 97	144,274	(133)	(14,953)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of shares withheld for tax payments (in shares)		53,000
Stock-based compensation, net of shares withheld for tax payments	835	$ 0	835
Unrealized gain (loss) on derivative financial instruments, net of tax	(89)			(89)
Tax payments related to stock-based awards	(168)		(168)
Net income (loss)	2,610				2,610
Balance (in shares) at Jun. 30, 2019		19,465,000
Balance at Jun. 30, 2019	132,473	$ 97	144,941	(222)	(12,343)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of shares withheld for tax payments (in shares)		1,000
Stock-based compensation, net of shares withheld for tax payments	336	$ 0	335
Unrealized gain (loss) on derivative financial instruments, net of tax	(25)			(25)
Net income (loss)	$ (1,224)				(1,224)
Balance (in shares) at Sep. 30, 2019	19,465,244	19,466,000
Balance at Sep. 30, 2019	$ 131,559	$ 97	$ 145,276	$ (247)	$ (13,567)