Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2013

Customers that Each Represented More Than 10% of Total Accounts Receivable

The Company had the following customers that each represented more than 10% of total accounts receivable:

	Years Ended December 31,						Nine Months Ended September 30,
	2011			2012			2012			2013
							(Unaudited)
Customer A		15	%		*	%		12	%		13	%
Customer B		10			*			*			10
		25	%		*	%		12	%		23	%

* Accounts receivable balance for an individual customer was less than 10% of total accounts receivable.

Company's Available-for-Sale Securities by Level Within the Fair Value Hierarchy

The Company’s available-for-sale securities by level within the fair value hierarchy were as follows:

As of September 30, 2013 (unaudited)	Fair value measurement using:
	Quoted prices in active markets for identical assets (Level 1)		Other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
	(In thousands)
Cash equivalents:
Money market fund	$	18,734	$	—	$	—	$	18,734
Short-term investments:
U.S. government-related debt securities		—		1,583		—		1,583
Corporate debt securities		—		31,339		—		31,339
Total	$	18,734	$	32,922	$	—	$	51,656

As of December 31, 2012	Fair value measurement using:
	Quoted prices in active markets for identical assets (Level 1)		Other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
	(In thousands)
Cash equivalents:
Money market fund	$	20,510	$	—	$	—	$	20,510
Preferred stock warrant liability	$	—	$	—	$	3,532	$	3,532

Reconcilation of Changes In Company's Warranty Reserve and Related Costs

The following information reconciles changes in the Company’s warranty reserve and related costs:

	(In thousands)
Warranty reserve, December 31, 2009	$	87
Cost of warranty claims		(173	)
Warranty accrual		149
Warranty reserve, December 31, 2010		63
Cost of warranty claims		(518	)
Warranty accrual		622
Warranty reserve, December 31, 2011		167
Cost of warranty claims		(244	)
Warranty accrual		325
Warranty reserve, December 31, 2012		248
Cost of warranty claims (unaudited)		(130	)
Warranty accrual (unaudited)		173
Warranty reserve, September 30, 2013 (unaudited)	$	291

Short-term investments

Company's Available-for-Sale Securities by Level Within the Fair Value Hierarchy

Short-term investments consisted of available-for-sale securities as follows:

Type of security as of September 30, 2013 (unaudited)	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	(In thousands)
U.S. government-related debt securities	$	1,581	$	2	$	—		$	1,583
Corporate debt securities		31,336		11		(8	)		31,339
Total available-for-sale securities	$	32,917	$	13	$	(8	)	$	32,922