Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2014

Changes in Warranty Liability

Changes in the Company’s warranty liability for the six months ended June 30, 2014 and 2013 are as follows:

(in thousands)	2014			2013
Warranty liability, January 1	$	597		$	346
Provisions for current year sales		112			208
Current period claims		(120	)		(87	)
Warranty liability, June 30	$	589		$	467

Summary of Changes in Allowance for Doubtful Accounts

The following summarizes the changes in the allowance for doubtful accounts for the periods indicated:

(in thousands)	2014			2013
Allowance for doubtful accounts, January 1	$	210		$	57
Additions		45			11
Write-offs		(42	)		(6	)
Allowance for doubtful accounts, June 30	$	213		$	62

Estimated Useful Lives of Property and Equipment

The estimated useful lives of property and equipment are as follows:

	Estimated useful lives
Machinery and equipment	3-7 years
Furniture and fixtures	5-7 years
Computers and software	3-7 years
Motor vehicles	5 years
Leasehold improvements	Lesser of lease term or estimated useful life

Valuation Assumptions used in Computation of Stock Option Expense

For the six months ended June 30, 2014, the Company computed expense for each group utilizing the following assumptions:

	Six Months Ended June 30, 2014
Expected volatility	75.8 – 81.1 %
Weighted-average volatility	76.0 %
Risk-free interest rate	0.4 – 0.9 %
Expected dividend	0 %
Expected life in years	3.5 – 8.6 Years