Summary of Significant Accounting Policies (Tables)
 6 Months Ended
Jun. 30, 2015
Accounting Policies [Abstract]  
Schedule of changes in the allowance for doubtful accounts
The following table presents the changes in the allowance for doubtful accounts for the three and six months ended June 30 (in thousands):
 
Three Months
Ended June 30,
 
Six Months
Ended June 30,
 
2014
 
2015
 
2014
 
2015
Allowance for doubtful accounts:
 
 
 
 
 
 
 
Balance, beginning of period
$
706

 
$
173

 
$
716

 
$
179

Add: adjustment for bad debts
—

 
—

 
—

 
—

Less: write-offs, net of recoveries
(290
)
 
(14
)
 
(300
)
 
(20
)
Balance, end of period
$
416

 
$
159

 
$
416

 
$
159
Schedule of changes in level 3 instruments
The following table presents the changes in the Company’s Lender Warrants measured at fair value on a recurring basis during the six months ended June 30 (in thousands):
 
2015
Balance as of January 1
$
1,615

Change in fair value of Lender Warrants liability
(482
)
Reclassification of Lender Warrants to equity
(1,133
)
Balance as of June 30
$
—

The following table presents the changes in the recorded liability associated with certain of the Company’s stock option awards which, as described in Note 6, have been accounted for as liability-based awards during the six months ended June 30 (in thousands):
 
2015
Balance as of January 1
$
461

Change in fair value of stock options classified as liability awards
(173
)
Reclassification of stock options classified as liability awards to equity
(288
)
Balance as of June 30
$
—
Schedule of assumptions used
The following table summarizes the assumptions used for estimating the fair value of the Lender Warrants and the stock options classified as liability awards for the six months ended June 30, 2015:
 
Lender
Warrants
 
Stock Option
Liability
Awards
Risk-free interest rate
1.97%
 
1.46% - 1.67% 
Expected term (years)
9.34
 
4.74 - 6.03
Expected volatility
58%
 
51% - 53% 
Dividend yield
—%
 
—%