Balance Sheet Components

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Investments

The fair value of the Company's available-for-sale investments as of December 31, 2020 and 2019 are as follows (in thousands):


	December 31, 2020
			Gross Unrealized				Estimated
	Amortized Cost		Gains		Losses		Fair Value
Money market funds	$	60,295	$	—	$	—	$	60,295
Commercial paper	39,577		—		—		39,577
Corporate bonds/notes	7,970		—		(1)		7,969
U.S. government securities	38,430		42		(2)		38,470
	$	146,272	$	42	$	(3)	$	146,311

Classified as:
Cash equivalents							$	68,295
Short-term investments							78,016
							$	146,311


	December 31, 2019
			Gross Unrealized				Estimated
	Amortized Cost		Gains		Losses		Fair Value
Money market funds	$	34,363	$	—	$	—	$	34,363
Commercial paper	9,919		—		—		9,919
Corporate bonds/notes	10,180		—		(4)		10,176
U.S. government securities	44,450		9		(3)		44,456
Asset-backed securities	5,181		—		—		5,181
	$	104,093	$	9	$	(7)	$	104,095

Classified as:
Cash equivalents							$	34,363
Short-term investments							51,508
Long-term investments							18,224
							$	104,095

The following table summarizes the fair value of the Company’s cash equivalents, short-term and long-term investments classified by maturity as of December 31, 2020 and 2019 (in thousands):


	December 31,
	2020		2019
Amounts maturing within one year	$	146,311	$	85,871
Amounts maturing after one year through two years	—		18,224
	$	146,311	$	104,095

Available-for-sale investments held as of December 31, 2020 had a weighted average days to maturity of 135 days.

The following table presents the Company's available-for-sale investments that were in an unrealized loss position as of December 31, 2020 and 2019 (in thousands):


	December 31, 2020				December 31, 2019
	Less than 12 months				Less than 12 months
Assets:	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds/notes	$	5,369	$	(1)	$	10,128	$	(4)
U.S. government securities	10,128		(2)		19,067		(3)
	$	15,497	$	(3)	$	29,195	$	(7)

Inventories

Components of inventories were as follows (in thousands):


	December 31,
	2020		2019
Raw materials	$	1,785	$	1,203
Finished products	10,599		9,163
	12,384		10,366
Less: Reserve for excess and obsolete	(2,395)		(44)
	$	9,989	$	10,322

As of December 31, 2020 and 2019, there were no work-in-process inventories. The reserve for excess and obsolete inventory at December 31, 2020, included $2,377,000 associated with the Company's voluntary product recall (see Note 14 - Subsequent Events).

Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	December 31,
	2020		2019
Furniture and fixtures	$	726	$	657
Equipment	1,699		1,295
Software	226		18
Leasehold improvements	2,043		1,991
	4,694		3,961
Less: Accumulated depreciation and amortization	(2,332)		(1,550)
Add: Construction-in-progress	482		323
	$	2,844	$	2,734

Depreciation and amortization expense was $789,000, $712,000 and $517,000 for the years ended December 31, 2020, 2019 and 2018, respectively.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):


	December 31,
	2020		2019
Accrued payroll and related expenses	$	9,573	$	9,151
Provision for sales returns	820		2,419
Accrued professional services	2,520		682
Recall replacement obligation	1,696		—
Operating lease liability	850		769
Accrued royalty expense	518		470
Deferred revenue	206		304
Accrued travel expenses	237		431
Accrued clinical expenses	113		241
Accrued other expenses	424		567
	$	16,957	$	15,034