Nature of Business and Summary of Significant Accounting Policies (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Number of shares outstanding for calculation of earnings (loss) per share
Basic net income and earnings per share, Numerator (Income)	$ 10,850	$ 8,272
Basic net income and earnings per share, Denominator (shares)	14,813,186	14,386,410
Basic net income and earnings per share, per share amount	$ 0.73	$ 0.58
Effect of dilutive securities and notes:
Common stock equivalents arising from stock options and employee stock purchase plan	327	124
Subordinated convertible promissory notes, Numerator (Income)	303	375
Subordinated convertible promissory notes, Denominator (shares)	2,106	2,605
Subordinated convertible promissory notes, Per Share Amount	$ (0.08)	$ (0.07)
Diluted earnings and earnings per share, Numerator (Income)	$ 11,153	$ 8,647
Diluted earnings and earnings per share, Denominator (shares)	17,246,058	17,115,284
Diluted earnings and earnings per share, Per Share Amount	$ 0.65	$ 0.51