Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Components [Abstract]
Fair Value of the Available-For-Sale Investments	September 30, 2021 Gross Unrealized Estimated Amortized Cost Gains Losses Fair ValueMoney market funds $ 105,629  $—  $—  $ 105,629 Commercial paper 2,000  —  —  2,000 U.S. government securities 15,126  1  —  15,127  $ 122,755  $ 1  $ — $ 122,756 Classified as: Cash equivalents $ 105,629 Short-term investments 17,127  $ 122,756  December 31, 2020 Gross Unrealized Estimated Amortized Cost Gains Losses Fair ValueMoney 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
Available-For-Sale Investments in Unrealized Loss Position	September 30, 2021 December 31, 2020 Less than 12 months Less than 12 monthsAssets:Fair Value Unrealized Loss Fair Value Unrealized LossCorporate bonds/notes $ — $ — $ 5,369 $ (1)U.S. government securities — — 10,128 (2) $ — $ — $ 15,497 $ (3)
Schedule of Inventories	September 30, December 31, 2021 2020Raw materials$ 2,195  $ 1,785 Finished products 13,876  10,599  16,071  12,384 Less: Reserve for excess and obsolete (23) (2,395) $ 16,049  $ 9,989
Schedule of Accrued Liabilities	September 30, December 31, 2021 2020Accrued payroll and related expenses$ 10,228 $ 9,573 Provision for sales returns 410 820 Accrued professional services 1,909 2,520 Recall replacement obligation 15 1,696 Operating lease liability 1,003 850 Accrued royalty expense 608 518 Deferred revenue 448 206 Accrued travel expenses 552 237 Accrued clinical expenses 150 113 Accrued other expenses 688 424 Total$ 16,011 $ 16,957