CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance (in shares) at Dec. 31, 2016		19,261,000
Balance at Dec. 31, 2016	$ 119,661,000	$ 96,000	$ 140,687,000	$ (262,000)	$ (20,860,000)
Stockholders' Equity [Roll Forward]
Issuance of shares under stock plans, net of shares withheld for tax payments (in shares)		25,000
Adoption of accounting standards (see Note 13)	220,000	$ 0	220,000
Stock-based compensation, net of shares withheld for tax payments (in shares)		24,000
Issuance of shares under stock plans, net of shares withheld for tax payments	1,316,000	$ 0	1,316,000
Unrealized gains on derivative financial instruments, net of tax	98,000			98,000
Tax payments related to stock-based awards	27,000		(27,000)
Net income (loss)	9,523,000
Balance (in shares) at Dec. 31, 2017		19,310,000
Balance at Dec. 31, 2017	130,791,000	$ 96,000	142,196,000	(164,000)	(11,337,000)
Stockholders' Equity [Roll Forward]
Issuance of shares under stock plans, net of shares withheld for tax payments (in shares)		42,000
Adoption of accounting standards (see Note 13)	425,000	$ 300	425,000
Stock-based compensation, net of shares withheld for tax payments (in shares)		31,000
Issuance of shares under stock plans, net of shares withheld for tax payments	1,484,000	$ 200	1,484,000
Unrealized gains on derivative financial instruments, net of tax	78,000			78,000
Tax payments related to stock-based awards	92,000		(92,000)
Net income (loss)	$ 4,142,000
Balance (in shares) at Dec. 31, 2018	19,382,641	19,383,000
Balance at Dec. 31, 2018	$ 136,435,000	$ 97,000	144,013,000	(86,000)	(7,589,000)
Stockholders' Equity [Roll Forward]
Issuance of shares under stock plans, net of shares withheld for tax payments (in shares)		30,000
Adoption of accounting standards (see Note 13)	249,000	$ 0	249,000
Stock-based compensation, net of shares withheld for tax payments (in shares)		83,000
Issuance of shares under stock plans, net of shares withheld for tax payments		$ 0	2,006,000
Unrealized gains on derivative financial instruments, net of tax	(121,000)
Tax payments related to stock-based awards	344,000		(345,000)
Net income (loss)	$ (12,919,000)
Balance (in shares) at Dec. 31, 2019	19,495,907	19,496,000
Balance at Dec. 31, 2019	$ 125,305,000	$ 97,000	$ 145,923,000	$ (207,000)	$ (20,508,000)