Restatement of previously issued financial statements due to correction of errors (Details 3) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2012
Dec. 31, 2011
Cash flows from operating activities:                
Net income $ 7,082 $ 709 $ 609 $ (409) $ (664) $ (561) $ 10,653 $ (1,468)
Adjustments to reconcile net income to net cash provided by operating activities:                
Impairment recovery on note receivable from shareholder         0     0
Deferred taxes             (5,440) 0
Excess tax benefits realized from share-based compensation             (844) 0
Depreciation and amortization             1,187 579
Share-based compensation             1,384 908
Allowance for doubtful accounts             50 0
Changes in operating assets and liabilities:                
Accounts receivable             (431) (947)
Deferred commissions             152 (1,512)
Prepaid expenses and other assets             (470) (470)
Security deposits             (127) 129
Accounts payable and accrued expenses             1,221 2,195
Income taxes payable             2,236 0
Deferred revenue             13,065 7,513
Other             160 13
Net cash provided by operating activities             22,796 6,940
Cash flows from investing activities:                
Purchases of property and equipment             (2,460) (663)
Net cash used in investing activities             (2,460) (663)
Cash flows from financing activities:                
Repayment of note receivable from shareholder             3,072 4
Payment of preferred stock dividend             (120) (159)
Proceeds from exercise of stock options and purchase of shares under stock purchase plan             575 19
Excess tax benefits realized from share-based compensation             844 0
Repayments of obligations under capital leases             (254) (96)
Payments of obligations under software licensing agreements             (145) (72)
Repurchase of common stock             0 (250)
Net cash provided by financing activities             3,972 (554)
Effect of exchange rates on cash and cash equivalents             72 (4)
Net increase in cash and cash equivalents             24,380 5,719
Cash and cash equivalents at beginning of year     8,931     3,212 8,931 3,212
Cash and cash equivalents at end of year             33,311 8,931
Supplemental disclosure of cash flow information:                
Interest             33 27
Income taxes             212 51
Supplemental disclosure of noncash investing and financing activities:                
Tender of common stock in lieu of interest payment on note receivable from shareholder             200 0
Capital contribution in lieu of preferred stock dividend             240 200
Property and equipment acquired under capital leases             1,024 118
Acquisition of software licenses             0 389
Accounts payable for property and equipment             0 742
Scenario, Previously Reported [Member]
                
Cash flows from operating activities:                
Net income 2,903 1,458 1,900 325 1,009 (188) 9,141 3,303
Adjustments to reconcile net income to net cash provided by operating activities:                
Impairment recovery on note receivable from shareholder         (1,200)     (1,200)
Deferred taxes             463 (1,154)
Excess tax benefits realized from share-based compensation             (930)  
Depreciation and amortization             1,216 592
Share-based compensation             1,384 908
Allowance for doubtful accounts             0  
Changes in operating assets and liabilities:                
Accounts receivable             (1,061) (1,462)
Deferred commissions             0 0
Prepaid expenses and other assets             (317) (470)
Security deposits             (127) 129
Accounts payable and accrued expenses             1,324 625
Income taxes payable             2,601 22
Deferred revenue             9,086 5,646
Other             (68) 2
Net cash provided by operating activities             22,712 6,940
Cash flows from investing activities:                
Purchases of property and equipment             (2,460) (663)
Net cash used in investing activities             (2,460) (663)
Cash flows from financing activities:                
Repayment of note receivable from shareholder             3,072 4
Payment of preferred stock dividend             (120) (159)
Proceeds from exercise of stock options and purchase of shares under stock purchase plan             575 19
Excess tax benefits realized from share-based compensation             930  
Repayments of obligations under capital leases             (254) (96)
Payments of obligations under software licensing agreements             (145) (72)
Repurchase of common stock               (250)
Net cash provided by financing activities             4,058 (554)
Effect of exchange rates on cash and cash equivalents             70 (4)
Net increase in cash and cash equivalents             24,380 5,719
Cash and cash equivalents at beginning of year     8,931     3,212 8,931 3,212
Cash and cash equivalents at end of year             33,311 8,931
Supplemental disclosure of cash flow information:                
Interest             33 27
Income taxes             212 51
Supplemental disclosure of noncash investing and financing activities:                
Tender of common stock in lieu of interest payment on note receivable from shareholder             200  
Capital contribution in lieu of preferred stock dividend             240 440
Property and equipment acquired under capital leases             2,309 118
Acquisition of software licenses               435
Accounts payable for property and equipment               742
Restatement Adjustment [Member]
                
Cash flows from operating activities:                
Net income 4,179 (749) (1,291) 734 (1,673) (373) 1,512 (4,771)
Adjustments to reconcile net income to net cash provided by operating activities:                
Impairment recovery on note receivable from shareholder         1,200     1,200
Deferred taxes             (5,903) 1,154
Excess tax benefits realized from share-based compensation             86  
Depreciation and amortization             (29) (13)
Share-based compensation             0 0
Allowance for doubtful accounts             50  
Changes in operating assets and liabilities:                
Accounts receivable             630 515
Deferred commissions             152 (1,512)
Prepaid expenses and other assets             (153) 0
Security deposits             0 0
Accounts payable and accrued expenses             (103) 1,570
Income taxes payable             (365) (22)
Deferred revenue             3,979 1,867
Other             228 11
Net cash provided by operating activities             84 0
Cash flows from investing activities:                
Purchases of property and equipment             0 0
Net cash used in investing activities             0 0
Cash flows from financing activities:                
Repayment of note receivable from shareholder             0 0
Payment of preferred stock dividend             0 0
Proceeds from exercise of stock options and purchase of shares under stock purchase plan             0 0
Excess tax benefits realized from share-based compensation             (86)  
Repayments of obligations under capital leases             0 0
Payments of obligations under software licensing agreements             0 0
Repurchase of common stock               0
Net cash provided by financing activities             (86) 0
Effect of exchange rates on cash and cash equivalents             2 0
Net increase in cash and cash equivalents             0 0
Cash and cash equivalents at beginning of year     0     0 0 0
Cash and cash equivalents at end of year             0 0
Supplemental disclosure of cash flow information:                
Interest             0 0
Income taxes             0 0
Supplemental disclosure of noncash investing and financing activities:                
Tender of common stock in lieu of interest payment on note receivable from shareholder             0  
Capital contribution in lieu of preferred stock dividend             0 (240)
Property and equipment acquired under capital leases             (1,285) 0
Acquisition of software licenses               (46)
Accounts payable for property and equipment               $ 0